Statistics Questions

5 A teacher uses a program that randomly chooses a student in the class to volunteer to answer a question The teacher will stop choosing students once a student gets the right answer but if the teacher is given ou answers in a row he will stop and help the class himself He estimates that 79 of the students in the class know the correct answer Assume that students are chosen with replacement Complete parts a through c below a Create a probability model for the number of students the teacher will call on until he receives the correct answer or stops to help the class 1 3 4 0 2 Number of students Probability Type integers or decimals Do not round b Find the expected number of students called on The expected number of students called on is Round to two decimal places as needed c Find the expected number of wrong answers that will be offered The expected number of wrong answers offered is Round to two decimal places as needed

The function f x log 4 6 is graphed below Plot all lattice points of the inverse Use the labeled points as your guide Answer Attempt 2 out of 2 Click on the graph to plot a point Click a point to delete it 10 9 8 M 6 15 13 20 1 8 8 11 2 3 4 5 6 8 The inverse can be given by the function f x 3 x 6 4 V It has a vertical The range of the function is 4 and it is decreasing on its domain of 4 V asymptote of x v 4

USE SALT A report set a goal of 0 541 for the proportion of babies still being breastfed one year after birth The organization also used the survey data to estimate the proportion who were still being breastfed one year after birth to be 0 351 for babies born in a particular year Suppose that the survey used a random sample of 1 000 parents and that you want to use the survey data to decide if there is evidence that the goal is not being met Let p denote the population proportion of all babies born in that particular year who were still breastfeeding at 12 months Hint See Example 10 10 The shape of the sampling distribution is approximately normal The sampling distribution is centered at 0 541 p 0 0158 a Describe the shape center and variability of the sampling distribution of p for random samples of size 1 000 if the null hypothesis Ho P 0 541 is true Round your standard deviation to four decimal places MY NOTES PRACTICE ANOTHER 0 We would not 8 this small or smaller is 0 0132 b Would you be surprised to observe a sample proportion as small as p 0 532 for a sample of size 1 000 if the null hypothesis Ho P 0 541 were true Explain why or why not Round your answer to four decimal places Consider the event surprising if the probability the event occurs when Ho P 0 541 is true is less than 0 05 be surprised to observe a sample proportion of p 0 532 for a sample of size 1 000 if the null hypothesis Ho P 0 541 is true The probability of a sample proportion X which is greater than 0 05 The standard deviation of the sampling distribution is c Would you be surprised to observe a sample proportion as small as p 0 507 for a sample of size 1 000 if the null hypothesis Ho p 0 541 were true Explain why or why not Round your answer to four decimal places Consider the event surprising if the probability the event occurs when Ho p 0 541 is true is less than 0 05 Since the probability of a sample proportion this small or smaller is 0 met We would 8 be surprised to observe a sample proportion of p 0 507 for a sample of size 1 000 if the null hypothesis Ho p 0 541 is true The probability of a sample proportion this small or smaller is which is less than 0 05 0 0 05 there is d The actual sample proportion observed in the study was p 0 351 Based on this sample proportion is there convincing evidence that the goal is not being met or is the observed sample proportion consistent with what you would expect to see when the null hypothesis is true Round your answer to four decimal places Consider the evidence that the goal is not being met convincing if the probability the event occurs when Ho p 0 541 is true is less than 0 05 which is less than 8 convincing evidence that the goal is not being

USE SALT A report set a goal of 0 541 for the proportion of babies still being breastfed one year after birth The organization also used the survey data to estimate the proportion who were still being breastfed one year after birth to be 0 351 for babies born in a particular year Suppose that the survey used a random sample of 1 000 parents and that you want to use the survey data to decide if there is evidence that the goal is not being met Let p denote the population proportion of all babies born in that particular year who were still breastfeeding at 12 months Hint See Example 10 10 The shape of the sampling distribution is approximately normal The sampling distribution is centered at 0 50 0 0224 x MY NOTES a Describe the shape center and variability of the sampling distribution of p for random samples of size 1 000 if the null hypothesis Ho P 0 541 is true Round your standard deviation to four decimal places PRACTICE ANOTHER b Would you be surprised to observe a sample proportion as small as p 0 532 for a sample of size 1 000 if the null hypothesis Ho P 0 541 were true Explain why or why not Round your answer to four decimal places Consider the event surprising if the probability the event occurs when Ho P 0 541 is true is less than 0 05 X The standard deviation of the sampling distribution is We would not 0 be surprised to observe a sample proportion of p 0 532 for a sample of size 1 000 if the null hypothesis Ho P 0 541 is true The probability of a sample proportion this small or smaller is which is greater than 0 05 c Would you be surprised to observe a sample proportion as small as p 0 507 for a sample of size 1 000 if the null hypothesis Ho P 0 541 were true Explain why or why not Round your answer to four decimal places Consider the event surprising if the probability the event occurs when Ho p 0 541 is true is less than 0 05 which is less than We would be surprised to observe a sample proportion of p 0 507 for a sample of size 1 000 if the null hypothesis Ho p 0 541 is true The probability of a sample proportion this small or smaller is which is less than 0 05 0 05 there is d The actual sample proportion observed in the study was p 0 351 Based on this sample proportion is there convincing evidence that the goal is not being met or is the observed sample proportion consistent with what you would expect to see when the null hypothesis is true Round your answer to four decimal places Consider the evidence that the goal is not being met convincing if the probability the event occurs when Ho P 0 541 is true is less than 0 05 Since the probability of a sample proportion this small or smaller is 0 convincing evidence that the goal is not being met

9 R 084 S In a survey on supernatural experiences 714 of 4 015 adult Americans surveyed reported that they had seen a ghost Assume that this sample is representative of the population of adult Americans USE SALT a Use the given information to estimate the proportion of adult Americans who would say they have seen a ghost Round your answer to three decimal places b Verify that the conditions for use of the margin of error formula to be appropriate are met The condition that the sample is a random sample from the population of interest or the sample is selected in a way that should result in a representative sample is met the sample size is large is met c Calculate the 95 margin of error Round your answer to three decimal places MY NOTES The condition that d Interpret the margin of error in context It is unlikely that the estimated proportion of all adult Americans who would say they have seen a ghost differs from the true population proportion by less than the value calculated above O It is impossible that the estimated proportion of all adult Americans who would say they have seen a ghost differs from the true population proportion by more than the value calculated above OIt is impossible that the estimated proportion of all adult Americans who would say they have seen a ghost differs from the true population proportion by less than the value calculated above It is unlikely that the estimated proportion of all adult Americans who would say they have seen a ghost differs from the true population proportion by more than the value calculated above It is likely that the estimated proportion of all adult Americans who would say they have seen a ghost differs from the true population proportion by the value calculated above Interpret the interval There is a 90 chance that the true proportion of all adult Americans who would say they have seen a ghost falls directly in the middle of this interval We are 90 confident that the mean number of all adult Americans who would say they have seen a ghost falls within this interval e Construct a 90 confidence interval for the proportion of all adult Americans who would say they have seen a ghost Enter your answer using interval notation Round your numerical values to three decimal places

4 In a survey on supernatural experiences 714 of 4 015 adult Americans surveyed reported that they had seen a ghost Assume that this sample is representative of the population of adult Americans USE SALT a Use the given information to estimate the proportion of adult Americans who would say they have seen a ghost Round your answer to three decimal places b Verify that the conditions for use of the margin of error formula to be appropriate are met The condition that the sample is a random sample from the population of interest or the sample is selected in a way that should result in a representative sample is met the sample size is large is met 8 c Calculate the 95 margin of error Round your answer to three decimal places MY NOTES The condition that d Interpret the margin of error in context It is unlikely that the estimated proportion of all adult Americans who would say they have seen a ghost differs from the true population proportion by less than the value calculated above It is impossible that the estimated proportion of all adult Americans who would say they have seen a ghost differs from the true population proportion by more than the value calculated above It is impossible that the estimated proportion of all adult Americans who would say they have seen a ghost differs from the true population proportion by less than the value calculated above It is unlikely that the estimated proportion of all adult Americans who would say they have seen a ghost differs from the true population proportion by more than the value calculated above It is likely that the estimated proportion of all adult Americans who would say they have seen a ghost differs from the true population proportion by the value calculated above Interpret the interval There is a 90 chance that the true proportion of all adult Americans who would say they have seen a ghost falls directly in the middle of this interval We are 90 confident that the mean number of all adult Americans who would say they have seen a ghost falls within this interval would say thou have coon a ghost falls within this interval e Construct a 90 confidence interval for the proportion of all adult Americans who would say they have seen a ghost Enter your answer using interval notation Round your numerical values to three decimal places

The company Digital Trends reported that 48 of Americans have shared passwords for TV and movie streaming t For purposes of this exercise assume that the 48 figure is correct for the population of adult Americans a A random sample of size n 500 will be selected from this population and p the proportion who have shared TV and movie streaming passwords will be calculated What are the mean and standard deviation of the sampling distribution of p Round your standard deviation to four decimal places mean standard deviation b Is the sampling distribution of p approximately normal for random samples of size n 500 Explain The sampling distribution of p is approximately normal because np is less than 10 The sampling distribution of p is approximately normal because np and n 1 p are both at least 10 The sampling distribution of p is not approximately normal because np is less than 10 O The sampling distribution of p is not approximately normal because np and n 1 p are both at least 10 The sampling distribution of p is not approximately normal because n 1 p is less than 10 c Suppose that the sample size is n 125 rather than n 500 What are the values of the mean and standard deviation when n 125 Round your standard deviation to four decimal places mean standard deviation Does the change in sample size affect the mean and standard deviation of the sampling distribution of p If not explain why not Select all that apply When the sample size decreases the mean increases MY NOTES When the sample size decreases the mean decreases When the sample size decreases the mean stays the same The sampling distribution is always centered at the population mean regardless of sample size When the sample size decreases the standard deviation increases When the sample size decreases the standard deviation decreases When the sample size decreases the standard deviation stays the same The standard deviation of the sampling distribution is always the same as the standard deviation of the population distribution regardless of sample size d Is the sampling distribution of p approximately normal for random samples of size n 125 Explain The sampling distribution of p is approximately normal because np is less than 10 The sampling distribution of p is approximately normal because np and n 1 p are both at least 10

The company Digital Trends reported that 48 of Americans have shared passwords for TV and movie streaming t For purposes of this exercise assume that the 48 figure is correct for the population of adult Americans a A random sample of size n 500 will be selected from this population and p the proportion who have shared TV and movie streaming passwords will be calculated What are the mean and standard deviation of the sampling distribution of p Round your standard deviation to four decimal places mean standard deviation b Is the sampling distribution of p approximately normal for random samples of size n 500 Explain The sampling distribution of p is approximately normal because np is less than 10 The sampling distribution of p is approximately normal because np and n 1 p are both at least 10 The sampling distribution of p is not approximately normal because np is less than 10 The sampling distribution of p is not approximately normal because np and n 1 p are both at least 10 The sampling distribution of p is not approximately normal because n 1 p is less than 10 MY NOTES c Suppose that the sample size is n 125 rather than n 500 What are the values of the mean and standard deviation when n 125 Round your standard deviation to four decimal places mean standard deviation Does the change in sample size affect the mean and standard deviation of the sampling distribution of p If not explain why not Select all that apply When the sample size decreases the mean increases When the sample size decreases the mean decreases When the sample size decreases the mean stays the same The sampling distribution is always centered at the population mean regardless of sample size When the sample size decreases the standard deviation increases When the sample size decreases the standard deviation decreases When the sample size decreases the standard deviation stays the same The standard deviation of the sampling distribution is always the same as the standard deviation of the population distribution regardless of sample size d Is the sampling distribution of p approximately normal for random samples of size n 125 Explain The sampling distribution of p is approximately normal because np is less than 10 The sampling distribution of p is approximately normal because np and n 1 p are both at least 10

PRACTICE ANOTHER Concentration is a one person memory game in which cards are laid facedown on a surface and two cards are flipped faceup at a time The object of the game is to turn over matching pairs of cards An online version of the game has two different versions one shows pictures of animals on the cards and one shows pictures of babies Student researchers wanted to investigate whether the two versions of the game are equally difficult so they recruited a sample of 26 participants and asked each participant to try both versions of the game in a random order Sixteen of the participants finished the version with animals on the cards faster than the version with babies on the cards Do these data provide convincing evidence that one version of the game is easier than the other Test the appropriate hypotheses using a significance level of a 0 1 You may assume that the participants in the study are representative of a larger population H USE SALT State the appropriate null and alternative hypotheses Let p be the population proportion of individuals who finish the version with animals on the cards faster than the version with babies on the cards Enter for as needed Ho p 0 5 p 0 5 Find the test statistic Round your answer to two decimal places MY Use technology to find the P value Round your answer to four decimal places P value State the conclusion in the problem context Reject Ho We have convincing evidence that one version of the game is easier than the other Reject Ho We do not have convincing evidence that one version of the game is easier than the other Fail to reject H We have convincing evidence that one version of the game is easier than the other Fail to reject H We do not have convincing evidence that one version of the game is easier than the other

An article included data from a survey of 188 senior managers in a range of industries In this sample only 28 managers reported that their meetings are generally productive uses of group and individual time USE SALT a Do these data provide convincing evidence that fewer than one quarter of all senior managers in the United States believe that their meetings are generally productive Use the five step process for hypothesis testing HMC described in this section and a 0 05 to test the appropriate hypotheses You may assume that the sample is representative of all senior managers in the United States State the appropriate null and alternative hypotheses Let p be the population proportion of all senior managers in the United States who believe that their meetings are generally productive Enter for as needed Ho H Find the test statistic Round your answer to two decimal places Use technology to find the P value Round your answer to four decimal places P value State the conclusion in the problem context Fail to reject Ho We do not have convincing evidence that fewer than one quarter of all senior managers in the United States believe that their meetings are generally productive Reject Ho We do not have convincing evidence that fewer than one quarter of all senior managers in the United States believe that their meetings are generally productive Reject Ho We have convincing evidence that fewer than one quarter of all senior managers in the United States believe that their meetings are generally productive O Fail to reject Ho We have convincing evidence that fewer than one quarter of all senior managers in the United States believe that their meetings are generally productive b Based on the results of the hypothesis test is it appropriate to conclude that the proportion of all senior managers in the United States who believe their meetings are generally productive is a lot less than 0 25 OYes Since the hypothesis test rejected the null hypothesis we can definitively conclude that that the proportion of all senior managers in the United States who believe their meetings are generally productive is a lot less than 0 25 that the proportion of all senior managers in the United States who believe their meetings

A report describes a survey of 500 licensed drivers Each driver in the sample was asked if they would prefer to keep complete control of the car while driving to use a partially self driving car that allowed partial driver control or to turn full control over to a driverless car Suppose that it is reasonable to regard this sample as a random sample of licensed drivers in the United States and that you want to use the data from this survey to decide if there is evidence that fewer than half of all licensed drivers in the United States prefer to keep complete control of the car while driving LUSE SALT a Describe the shape center and variability of the sampling distribution of p for random samples of size 500 if the null hypothesis Ho p 0 50 is true Round your standard deviation to four decimal places The shape of the sampling distribution is approximately normal The sampling distribution is centered at We would not 0 small or smaller is b Would you be surprised to observe a sample proportion as small as p 0 49 for a sample of size 500 if the null hypothesis Ho p 0 50 were true Explain why or why not Consider the event surprising if the probability that the event occurs when Ho p 0 5 is true is less than 0 05 Round your answer to four decimal places MY NOTES The standard deviation of the sampling distribution is We would small or smaller is be surprised to observe a sample proportion of p 0 49 for a sample of size 500 if the null hypothesis Ho P 0 5 is true The probability of a sample proportion this which is greater than the signficance level of 0 05 c Would you be surprised to observe a sample proportion as small as p 0 46 for a sample of size 500 if the null hypothesis Ho p 0 50 were true Explain why or why not Consider the event surprising if the probability that the event occurs when Ho p 0 5 is true is less than 0 05 Round your answer to four decimal places O be surprised to observe a sample proportion of p 0 46 for a sample of size 500 if the null hypothesis Ho P 0 5 is true The probability of a sample proportion this which is less than B the signficance level of 0 05 which is less than Since the probability of a sample proportion this small or smaller is fewer than 50 of licensed drivers prefer to keep complete control of the car when driving d The actual sample proportion observed in the study was p 0 44 Based on this sample proportion is there convincing evidence that fewer than 50 of licensed drivers prefer to keep complete control of the car when driving or is the sample proportion consistent with what you would expect to see when the null hypothesis is true Support your answer with a probability calculation Round your answer to four decimal places Consider the that fewer than 50 of licensed drivers prefer to keep complete control of the car when driving convincing if the probability that the event occurs when Ho p 0 5 is true is less than 0 05 the signficance level of 0 05 there is 0 convincing evidence that

The article The World Prefers a Calm Life to an Exciting Life reports the results of a survey by the Wellbeing for Planet Earth WPE Foundation that asked adults from 116 countries and territa around the world Would you rather live an exciting life or a calm life The resulting data were used to test Ho p 0 5 versus H p 0 5 and the null hypothesis was rejected a a Based on the title of the article what do you think p represents in the hypotheses Hint Make sure to distinguish between a sample statistic and a population parameter Op represents the number of adults from the 116 countries and territories from around the world who would rather live a calm life Op represents the number of adults who responded to the survey who indicated they would rather live a calm life Op represents the proportion of the population of adults who responded to the survey who indicated they would rather live a calm life Op represents the number of adults from every country and territory on Earth who would rather live a calm life Op represents the proportion of the population of adults from the 116 countries and territories from around the world who would rather live a calm life b Is it reasonable to say that the data provide strong support for the alternative hypothesis Yes since the null hypothesis was not rejected it is reasonable to say the data provide strong support for the alternate hypothesis Yes since the null hypothesis was rejected it is reasonable to say the data provide strong support for the alternate hypothesis No since the null hypothesis was rejected it is not reasonable to say the data provide strong support for the alternate hypothesis O No since the null hypothesis was not rejected it is not reasonable to say the data provide strong support for the alternate hypothesis O Since we have not seen the actual data we cannot say whether it is reasonable or not to say the data provide strong support for the alternate hypothesis c Is it reasonable to say that the data provide strong evidence against the null hypothesis O Yes since the null hypothesis was rejected it is reasonable to say that the data provide strong evidence against the null hypothesis Yes since the null hypothesis was not rejected it is reasonable to say that the data provide strong evidence against the null hypothesis O No since the null hypothesis was rejected it is not reasonable to say that the data provide strong evidence against the null hypothesis No since the null hypothesis was not rejected it is not reasonable to say that the data provide strong evidence against the null hypothesis Since we have not seen the actual data we cannot say whether it is reasonable or not to say that the data provide strong evidence against the null hypothesis ICE ANO OC

You may need to use the appropriate appendix table or technology to answer this question In a random sample of 400 residents of Chattanooga 350 residents indicated that they voted for the Democratic candidate in the last presidential election Develop a 95 confidence interval estimate for the proportion of all Chattanooga residents who voted for the Democratic candidate Round your answers to three decimal places to

4 Describe the end behavior of h x x 3 x 5 x 6

a What is the probability that a guitar neck can be carved between 95 and 165 minutes b What is the probability that the guitar neck can be carved between 130 and 180 minutes c Determine the expected completion time in minutes for carving the guitar neck min d Compute the standard deviation in minutes Round your answer to two decimal places Need Help Submit Answer min Read It

The driving time for an individual from his home to his work is uniformly distributed between 200 to 470 seconds a Determine the probability density function f x 0 b Compute the probability that the driving time will be less than or equal to 415 seconds Round your answer to two decimal places c Determine the expected driving time in seconds sec 200 x 470 elsewhere d Compute the variance e Compute the standard deviation in seconds Round your answer to two decimal places sec MY NOTES

You may need to use the appropriate appendix table or technology to answer this question The average U S daily internet use at home is two hours and twenty minutes A sample of 81 homes in a certain city showed an average usage of one hour and 40 minutes with a standard deviation of 90 minutes We are interested in determining whether or not the average usage in that city is significantly different from the U S average a State the null and alternative hypotheses in minutes to be tested Enter for as needed Ho 1 00 H b Compute the test statistic X 0 65 c The null hypothesis is to be tested using a 0 05 Determine the critical value s for this test Round your answer s to two decimal places If the test is one tailed enter NONE for the unused tail test statistic 2 58 test statistic 2 2 58 X X d What do you conclude O Reject Ho We can conclude that the average usage in that city is significantly different from the U S average O Do not reject Ho We can conclude that the average usage in that city is significantly different from the U S average O Do not reject Ho We cannot conclude that the average usage in that city is significantly different from the U S average Reject Ho We cannot conclude that the average usage in that city is significantly different from the U S average X

You may need to use the appropriate appendix table or technology to answer this question In a random sample of 400 registered voters 160 indicated they plan to vote for Candidate A Determine a 95 confidence interval for the proportion of all the registered voters who will vote Candidate A Round your answers to three decimal places to

You may need to use the appropriate appendix table or technology to answer this question In a sample of 400 registered voters 206 were Democrats a Provide a 95 confidence interval for the proportion of registered Democrats in the population Round your answers to five decimal places to b There are 169 million registered voters in the US Determine an interval for the number how many of registered Democrats in the population Round your answers to the nearest whole number Need Help to Read It

The random variable x is known to be uniformly distributed between 1 0 and 1 5 a Show the graph of the probability density function f x 3 f x 3 0 5 1 1 5 2 2 5 X Ax 0 5 1 1 5 2 2 5 Ax 1 0 5 1 1 5 2 2 5

Let x represent the sample mean hourly wage for a group of 90 females To be within 1 00 of the population mean of 27 83 gives a range of hourly wages between 27 83 1 00 26 83 26 83 and 27 83 1 00 28 83 28 83 Therefore the desired probability that a sample mean of 90 females is within 1 00 of the population mean is P 26 83 Step 5 The mean hourly wage for females is given to be 27 83 with a standard deviation of 4 10 Both values are representative of the population but we are to determine P 26 83 x 28 8 for a sample of 90 female graduates Since we are dealing with the probability for a sample mean x instead of a particular value of x the calculation for z will now account for the sample mean x and standard error o X Z Z Find the z value corresponding to x 26 83 rounding the result to two decimal placks x O Z n 26 83 27 83 X H ox 0 90 x Find the z value corresponding to x 28 83 rounding the result to two decimal places x 28 83 27 83 O n 26 83 x 28 83 28 83

The uniform distribution defined over the interval from 15 to 35 has which of the following probability density functions O f x O f x O f x O f x 1 35 3 for 15 x 35 and f x 0 elsewhere 7 1 15 for all x Need Help for 0 x 15 and f x Read It 1 35 1 for 15 x 35 and f x 0 elsewhere 20 for 16 x 35

To indirectly measure the distance across a river Makayla stands on one side of the river and uses sight lines to a landmark on the opposite bank Makayla draws the diagram below to show the lengths and angles that she measured Find PR the distance across the river Round your answer to the nearest foot R 165 ft 235 ft E

The time between arrivals of vehicles at a particular intersection follows an exponential probability distribution with a mean of 12 seconds a Sketch this exponential probability distribution f x 0 15 0 10 0 05 f x 0 15 0 10 0 05 5 10 15 20 25 30 X f x 0 15 0 10 0 05 5 10 question4265470 8 15 20 25 30 X f x 0 15 0 10 0 05 5 10 15 20 25 9 30

length of stay in the ICU is 3 3 days Assume that this length of stay in the ICU has an exponential distribution Round your answers to four decimal places a What is the probability that the length of stay in the ICU is one day or less b What is the probability that the length of stay in the ICU is between two and three days c What is the probability that the length of stay in the ICU is more than five days Need Help Submit Answer Read It DETAILS ASWSBE14 6 TB 4 011 5 2 5 Points The time it takes a mechanic to change the oil in a car is exponentially distributed with a mean of 13 minutes MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER

3 Define f x 1 for x in 0 50 0 50 f x 0 for x outside of 0 50 0 50 Let X be a continuous random variable with probability density function f x Determine whether the following statement is true or false P 0 X 50 is numerically equal to P 0 X 1 O True O False Continue Reset answer

2 Find the area between f x and the x axis over the entire real line Assume f x 0 for all x outside the interval 1 1 f x 1 Answer 2 1 X

Which of the following are continuous random variables I the weight of an elephant II the time to answer a questionnaire III the number of floors in a skyscraper IV the square feet of countertop in a kitchen I and II only III and IV only O I II and IV only O I II III and IV X

For a 95 confidence level the necessary value for z x za 2 0 x za 2 Step 4 We now have all the values necessary to find the upper and lower bounds for the confidence interval x 33 Za 2 1 960 o 7 and n 50 Substitute these values to first find the lower bound of the 95 confidence interval to two decimal places D 50 n 99 6 n 33 2 576 Now find the upper bound of the 95 confidence interval to two decimal places 50 33 is 1 960 Za 2 1 960 Submit Skip you cannot come back Thus a 95 confidence interval for the population mean in a sample of 50 items with a sample mean of 33 and a population standard deviation of 7 is to

The price of a stock is uniformly distributed between 50 and 60 a What is the probability that the stock price will be more than 57 0 4 X b What is the probability that the stock price will be less than or equal to 54 0 25 X c What is the probability that the stock price will be between 54 and 59 0 4167 X d Determine the expected price in dollars of the stock 55 e Determine the standard deviation in dollars for the stock price Round your answer to two decimal places 2 89

The time it takes a mechanic to change the oil in a car is exponentially distributed with a mean of 13 minutes a What is the probability density function for the time it takes to change the oil f x for x 0 b What is the probability that it will take a mechanic less than 14 minutes to change the oil Round your answer to four decimal places c What is the probability that it will take a mechanic between 11 and 13 minutes to change the oil Round your answer to four decimal places d What is the variance of the time it takes to change the oil

Consider the following exponential probability density function 1 f x e x 4 for x 0 a Write the formula for P x xo b Find P x 2 Round your answer to four decimal places c Find P x 4 Round your answer to four decimal places d Find P x 5 Round your answer to four decimal places e Find P 2 x 5 Round your answer to four decimal places

5 Number of Absences 0 3 4 Grade 5 5 5 4 3 5 6 2 5 Step 3 of 3 Calculate the coefficient of determination r Round your answer to three decimal places 7 8 2 1

The time it takes a worker on an assembly line to complete a task is exponentially distributed with a mean of 10 minutes a What is the probability density function for the time it takes to complete the task f x for x 0 MY TES b What is the probability that it will take a worker less than 5 minutes to complete the task Round your answer to four decimal places AS c What is the probability that it will take a worker between 8 and 12 minutes to complete the task Round your answer to four decimal places What

Suppose the following estimated regression equation was determined to predict salary based on years of experience Estimated Salary 23 237 70 2277 01 Years of Experience What is the estimated salary for an employee with 15 years of experience

The data in the table is the number of absences for 7 students and their corresponding grade 3 5 4 5 4 Number of Absences 0 1 Grade Step 1 of 3 Calculate the correlation coefficient r Round your answer to six decimal places 4 3 5 5 2 5 6 2 7 1 5

The time it takes to completely tune an engine of an automobile follows an exponential distribution with a mean of 30 minutes Round your answers to four decimal places a What is the probability of tuning an engine in 20 minutes or less b What is the probability of tuning an engine between 20 and 25 minutes

What is the mean of x given the function below f x 1 e x x O 0 11 09 O 81 O 729 X 0

What is the probability that x is between 4 and 6 given the function below e x 6 f x 0 0243 0 1100 0 1455 O 0 1469 x 0

You may need to use the appropriate appendix table or technology to answer this question The mean number of sick days an employee takes per year is believed to be about 10 Members of a personnel department do not believe this figure They randomly survey 8 employees The number of sick days they took for the past year are as follows 11 3 14 2 10 7 7 9 Let X the number of sick days they took for the past year Should the personnel team believe that the mean number is about 10 Conduct a hypothesis test at the 5 level State the null and alternative hypotheses in days Enter for as needed Ho H What is the test statistic Round your answer to two decimal places What is are the critical value s If using the z distribution round your answer s to two decimal places and if using the t distribution round your answer s to three decimal places Enter NONE for any unused answer blanks lower tail upper tail What is the decision of the test and what conclusions can be drawn O At the 5 level of significance we would fail to reject Ho and conclude that there is not sufficient evidence to conclude that the average number of sick days used equal to 10 days t by an ployee is not O At the 5 level of significance we would reject Ho and conclude that there is sufficient evidence to conclude that the average number of sick days used per year by an employee is not equal to 10 days O At the 5 level of significance we would reject Ho and conclude that there is not sufficient evidence to conclude that the average number of sick days used per year by an employee is not equal to 10 days At the 5 level of significance we would fail to reject Ho and conclude that there is sufficient evidence to conclude that the average number of sick days used per year by an employee is not equal to 10 days

You may need to use the appropriate appendix table or technology to answer this question The cost of a daily newspaper varies from city to city However the variation among prices remains steady with a standard deviation of 0 20 A study was done to test the claim that the mean cost of a daily newspaper is 1 00 Fifteen costs yield a mean cost of 0 97 with a standard deviation of 0 18 Do the data support the claim at the 1 level State the null and alternative hypotheses in dollars Enter for as needed Ho H What is the test statistic Round your answer to two decimal places What is are the critical value s If using the z distribution round your answer s to two decimal places and if using the t distribution round your answer s to three decimal places Enter NONE for any unused answer blanks lower tail upper tail What is the decision of the test and what conclusions can be drawn O At the 1 level of significance we would reject Ho and conclude that there is not sufficient evidence to conclude that the the average cost of a daily newspaper is not equal to 1 00 O At the 1 level of significance we would reject Ho and conclude that there is sufficient evidence to conclude that the the average cost of a daily newspaper is not equal to 1 00 O At the 1 level of significance we would fail to reject Ho and conclude that there is not sufficient evidence to conclude that the the average cost of a daily newspaper is not equal to 1 00 O At the 1 level of significance we would fail to reject Ho and conclude that there is sufficient evidence to conclude that the the average cost of a daily newspaper is not equal to 1 00

You may need to use the appropriate appendix table or technology to answer this question In order to determine the average price of hotel rooms in Atlanta a sample of 64 hotels was selected It was determined that the average price of the rooms in the sample was 107 20 with a standard deviation of 16 a Formulate the hypotheses in dollars to determine whether or not the average room price is significantly different from 111 Enter for as needed Ho H b Compute the test statistic c Using the p value approach test the hypotheses Let a 0 1 Find the p value Round your answer to four decimal places p value State your conclusion O Reject Ho There is insufficient evidence to conclude that the average room price is significantly different from 111 O Do not reject Ho There is sufficient evidence to conclude that the average room price is significantly different from 111 O Reject Ho There is sufficient evidence to conclude that the average room price is significantly different from 111 O Do not reject Ho There is insufficient evidence to conclude that the average room price is significantly different from 111

The following table shows students test scores on the first two tests in an introductory chemistry class First test x Answer Second test y Chemistry Test Scores 84 57 95 82 67 41 83 40 77 84 77 50 57 53 89 89 74 59 34 61 33 62 66 60 43 Copy Data Step 1 of 2 Find an equation of the least squares regression line Round your answer to three decimal places if necessary

The following data gives the number of hours 7 students spent studying and their corresponding grades on their midterm exams Hours Spent Studying 0 0 5 1 3 3 5 4 5 Midterm Grades 63 72 75 81 84 90 93 Calculate the correlation coefficient r Round your answer to three decimal places

A publisher reports that 54 of their readers own a personal computer A marketing executive wants to test the claim that the percentage is actually over the reported percentage A random sample of 330 found that 60 of the readers owned a personal computer Is there sufficient evidence at the 0 05 level to support the executive s claim Step 1 of 7 State the null and alternative hypotheses Answer Tables Keypad Keyboard Shortcuts

The following table gives the number of parking tickets obtained in a semester and the GPAS of 5 randomly selected drivers Number of Tickets 1 3 4 5 8 GPA 5 4 5 4 1 5 1 Calculate the coefficient of determination r2 Round your answer to three decimal places

The table below gives the number of hours five randomly selected students spent studying and their corresponding midterm exam grades Using this data consider the equation of the regression line bo b x for predicting the midterm exam grade that a student will earn based on the number of hours spent studying Keep in mind the correlation coefficient may or may not be statistically significant for the data given Remember in practice it would not be appropriate to use the regression line to make a prediction if the correlation coefficient is not statistically significant Hours Studying 0 1 2 3 5 Midterm Grades 66 74 86 87 95 Step 6 of 6 Find the value of the coefficient of determination Round your answer to three decimal places Table Copy Data

1 In the game of roulette a player can place a 6 bet on the number 1 and have a 38 probability of winning If the metal ball lands on 1 the player gets to keep the 6 paid to play the game and the player is awarded an additional 210 Otherwise the player is awarded nothing and th casino takes the player s 6 What is the expected value of the game to the player If you played the game 1000 times how much would you expect to lose Note that the expected value is the amount on average one would expect to gain or lose each game The expected value is Round to the nearest cent as needed The player would expect to lose about Round to the nearest cent as needed

Many universities use a student s ACT score to help with admission decisions as well as placement decisions ACT Score 18 20 24 26 28 30 32 1 1 5 2 5 3 3 5 4 5 GPA Step 3 of 3 Calculate the coefficient of determination 2 Round your answer to three decimal places Co

b Compute the probability of receiving exactly 10 calls in 20 minutes Now we are to find the probability of receiving 10 calls in a 20 minute interval It is given that on average 36 calls are received per hour so this must be converted to a 20 minute inter We previously found that on average there are 0 6 calls per minute To find the mean number of calls in a 20 minute interval multiply the mean number of calls per minute by 20 20 minutes mean number of calls per minute 20 Thus on the same 20 minute time interval we have Submit Skip you cannot come back Need Help Read It Submit Answer calls per 20 minutes and x