Statistics Questions and Answers

Karr and Coats studied the effects of several chemicals on the growth of the German cockroach the following table gives their data for the percent of the chemical a terpineol in the diet of 20 a terpineol Percent a terpineol 1 10 25 Days to Adult Stage 129 113 115 A On the basis of the data given in the table find the best fitting logarithmic function using least squares State the square of the correlation coefficient Use 4 decimal places in your answer y x B Use this model to estimate the days to adult stage with a diet of 20 a terpineol Round to the nearest day When a 20 a terpineol then there are days to adult stage

simple random sample of 45 CHS students is conducted The mean age of the sample was 194 months with a standard deviation of 7 months Q5 4 points Check the R N and I conditions Q6 6 points The conditions for inference have been met Construct a 95 confidence interval for the mean age of aterial

When using a one sample Z procedure using Z scores to construct a confidence interval for a population proportion we need to check that the sample proportions are Normally distributed Which of the following best represent the condition s for Normality in this case A The sample size must be greater than or equal to 30 B The product of np and n 1 p must be at least 10 C The data must come from a simple random sample D The sample must be no more than 10 of the population Q4 5 points A 2022 survey found that 300 out of 400 young adults read at least 5 books during 2021 We want to construct a 92 percent confidence interval for the proportion of all young adults who read at least 5 books during 2021 Which of the following represents that interval A 300 1 7507 0 75 0 25 400 3 300 1 4051 0 75 0 25 400 0 75 1 7507 0 75 0 25 400 0 75 1 4051 0 75 0 25 400

A simple random sample of 121 home prices in Central NJ is conducted and a 95 confidence interval for the mean price is 225 000 325 000 What is the mean selling price for the sample A 275 000 D 278 000 B 260 000 C 280 000 Q2 5 points A simple random sample of 400 home prices in Central NJ is conducted and a confidence interval for the mean price is 346 080 353 920 The mean selling price for the sample is 350 000 with a sample standard deviation of 40 000 What is the level of confidence for the confidence interval A 80 B 90 C 95 D 98

To test the effectiveness of a ne Construct a 90 confidence interval using the inequality d t Hd d c drug that is reported to increase the number of hours of sleep patients get during the night researchers randomly select 13 patients and record the number of hours of sleep each gets with and without the new drug Patient 1 2 Sleep without the drug 4 7 4 1 3 6 1 9 3 4 3 4 5 6 7 8 9 10 11 12 13 3 4 4 1 3 3 4 9 4 6 2 1 2 7 3 1 Sleep using the drug 5 3 5 2 5 9 3 0 4 9 4 3 6 6 4 6 6 6 5 9 3 8 3 5 4 5 Calculated for each patient by subtracting the number of hours of sleep with the drug from the number without the drug The confidence interval is Type an integer or a decimal Round to two decimal places as needed

Module 7 Two stical Inference Questio

lodule 7 Two stical Inference K Question 20 Part 1 o The pass completion percentages of are shown in the table below At a

43357 Module 7 Two tistical Inference 12 Question 19 Part 1 of 4 Test the claim below about the mean of

rk Module 7 Two Statistical Inference Ques

and Question 12 of 16 The weights in pounds of 6 vehicles and the variability of their brak you conclude that there is a significant linear correlation between ve Weight x 5920 5340 6500 5100 5870 1 77 1 97 1 85 1 58 1 63 Variability in braking distance y Click here to view a table of critical values for Student s t distrib

on and Question 1 of 16 The table shows the numbers of new vehicle sales in thousands regression line is y 0 985x 1 242 89 Complete parts a and b New vehicle sales Company A x New vehicle sales Company B y 4 160 3 878 3 4 921 4 873 4

You work for a company that produces electronics with integrated circuits One of your products is called a shift register This product is designed to automatically shut down if its operating temperature exceeds 175 degrees Celsius The manufacturing process has been designed to have a standard deviation of o 0 4 degrees Celsius You test a random sample 16 shift registers and you record the following shut down temperatures Construct a 90 confidence interval for the overall mean shutdown temperature 176 15 175 21 174 86 175 19 175 32 175 01 174 78 175 45 175 1 174 81 174 85 174 93 174 41 174 69 Checksum 2800 22 A Checksum is used as a way to check that you don t have a typo in the data you have entered After entering the data into Excel you can find the sum of the data using the equation SUM if it s different than what is shown above then you have a typo in the data and should fix it before continuing the problem What is the critical value 1 645 What is the margin of error 0 1645 What is the confidence interval 174 65 174 81 0 Y Part 2 of 3 Part 3 of 3

Question 11 of 16 companying data are the length in centimeters and girths in centimeters of ct a scatter plot of the data and draw the regression line Then use the regress ingful If the x value is not meaningful to predict the value of y explain why not x 140 cm b x 172 cm c x 164 cm d x 158 cm ick the icon to view the table of lengths and girths uation of the regression line is y x BIRKKIN

n and Question 13 of 16 The table shows the amounts of crude oil in thousands of barrels barrels per day imported by the same country for seven years Th below Produced x 5 801

A random number generator picks a number from 13 to 59 in a uniform manner Round answers to 4 decimal places when possible a The mean of this distribution is b The standard deviation is c The probability that the number will be exactly 52 is P x 52 d The probability that the number will be between 27 and 42 is P 27 x 42 e The probability that the number will be larger than 40 is P x 40 f P x 19 1 x 40 g Find the 9th percentile h Find the maximum for the lower quartile

on and r 0 463 Question 3 of 1 Use the value of the linear correlation coefficient to calculate th the data about the regression line About the unexplained vari

and Question 6 Describe the explained variation about a regression line in symbols

n and Question Identify the explanatory variable and the response var A golfer wants to determine if the amount of practice e

nd Question 5 of 10 scribe the total variation about a regression line in words an

nd bose the correct answer below Questi ich value of r indicates a stronger correlation r A r 0 803 represents a stronger correlation B r 0 893 represents a stronger correlatio C r 0 803 represents a stronger correlation

The duration of a professor s class has a continuous uniform distribution between 50 0 minutes and 52 0 minutes If one class is randomly selected find the probability that the professor s class duration is between 50 3 and 50 5 minutes P 50 3 X 50 5

11 review firs Percent Increase and Decrease Wor 17 Darren makes 12 per hour Nex increase does this represent Rou 18 Lowes in Rancho Cucamonga is h for an exterior do

The graph of a normally distributed random variable is given Use the graph to answer the questions that follow 35 40 What is the mean 45 What is the standard deviation 50 Which value has a z score of 2 55 60 What percentage of values should fall between 50 and 55 65 Q

For a 4 period class students should spend an average of 12 hours studying for the class A survey was done on students and the distribution of total study hours per week is bell shaped with a mean of 14 hours and a standard deviation of 3 hours Use the Empirical Rule to answer the following questions 68 of the students have study hours that are between and

A normal distribution has a mean of 134 and a standard deviation of 5 Find the z score for a data value of 153 Use the formula Z HIF where u is the mean o is the standard deviation and x is the data value Round to 4 decimal places

Question 4 Assume an investor has 10 000 doll which shows the probabilities for gai What would be the expected gain or metals

Questio mpany estimates that it has 300 in consultant fees to pre contract

dule 6 thesis Testing K Question 25 Part 1 of 5 A light bulb manufacturer guarantees th sample of 30 light bulbs has a mean life standard deviation is 57 hours At x 0 parts a through e

ork Module 6 ate Hypothesis Testing work list K Question 28 Part 1 of 2 Find the critical value s and rejection r Two tailed test 0 02 n 5 Click the icon to view the t distribu

s Testing Quest F A refrigerator manufacturer cla

e 6 esis Testing Ques State H and H in words a

work Module 6 riate Hypothesis Testing work

Suppose we want to choose 6 letters without replacement from 15 distinct letters If necessary consult a list of formulas a If the order of the choices is not relevant how many ways can this be done b If the order of the choices is relevant how many ways can this be done X

Stress at work In a poll conducted by the General Social Survey 81 of respondents said that their jobs were sometimes or always stressful Ten workers are chosen at random d Would it be unusual if fewer than 4 of them find their jobs stressful

A simple random sample of size n 1 120 is obtained from a population whose size is N 1 500 000 and whose population proportion with a specified characteristic is p 0 46 Describe the sampling distribution of p Round the standard deviation of the sampling distribution to three decimal places O A Approximately normal Hp 0 46 p 0 129 B Approximately normal Hp 0 46 p 0 015 O C Exactly normal Hp 0 46 p 0 015 O D Exactly normal p 0 46 p 0 129

What are the values of and o for the provided sampling distribution of the sample mean i Click here to view the samp OA H 310 a 40 OB 20 310 OC H 310 60 OD 310 20 x Sampling Distribution 290 4 310 330

Is the set of functions f x e 4 x ex 3 linearly dependent or linearly independent on Discuss Since e 3 ex 4 we see that ex 3 is x 4 a constant multiple of e and the set of functions is linearly dependent

What are the values of and for the provided sampling distribution of the sample mean ox Click here to view the sampling distribution of the sample mean O A 10 0 410 OB H 410 20 OC H 410 10 OD H 410 G 30 Sampling Distribution 400 410 420 h

Find the upper and lower limit of the confidence interval 0 173 0 034 then express it in inequality form Do not round P I

Teresa is in charge of planning a reception for 3600 people She is trying to decide which snacks to buy She has asked a random sample of people who are coming to the reception what their favorite snack is Here are the results Favorite Snack Brownies 31 Pretzels Potato chips Other Number of People people 34 27 55 64 Based on the above sample predict the number of the people at the reception whose favorite snack will be pretzels Round your answer to the nearest whole number Do not round any intermediate calculations X M

Determine and Hand o from the given parameters of the population and the sample size Round the answer to three decimal places where appropriate p 31 o 9 n 21 OA H 17 898 0 1 964 OB H 31 000 0 1 964 OC H 31 000 0 9 000 OD H 31 000 o 0 429

Smith is a weld inspector at a shipyard He knows from keeping track of good and substandard welds that for the afternoon shift 5 of all welds done will be substandard If Smith checks 300 of the 7500 welds completed that shift what is the probability that he will find between 10 and 20 substandard welds Round to four decimal places OA 0 2033 B 0 6377 OC 0 8147

A national caterer determined that 37 of the people who sampled their food said that it was delicious A random sample of 144 people is obtained from a population of 5000 The 144 people are asked to sample the caterer s food If p is the sample proportion saying that the food is delicious what is the standard deviation of the sampling distribution of p A 0 48 B 0 23 C 0 04 D 0 002

The amount of money collected by a snack bar at a large university has been recorded daily for the past five yea Records indicate that the mean daily amount collected is 4 850 and the standard deviation is 450 The distribu skewed to the right due to several high volume days including football game days Suppose that 100 days were randomly selected from the five years and the average amount collected from those days was recorded Which c following describes the sampling distribution of the sample mean OA normally distributed with a mean of 4 850 and a standard deviation of 450 OB normally distributed with a mean of 4 850 and a standard deviation of 45 OC normally distributed with a mean of 9 70 and a standard deviation of 45 O D skewed to the right with a mean of 4 850 and a standard deviation of 450

The owner of a computer repair shop has determined that their daily revenue has moan 7200 and standard deviation 1200 The daily revenue totals for the next 30 days will be monitored What is the probability that the mean daily revenue for the next 30 days will be less than 7000 Round to four decimal places OA 0 5675 B 0 4325 C 0 8186 OD 0 1807

If a school district takes a random sample of 69 Math SAT scores and finds that the average is 496 and knowing that the population standard deviation of Math SAT scores is intended to be 100 Find a 99 confidence interval for the mean math SAT score for this district Give your answers as decimals to two places What is the critical value

The age when smokers first start from previous studies is normally distributed with a mean of 13 years old with a population standard deviation of 2 1 years old A survey of smokers of this generation was done to estimate if the mean age has changed The sample of 30 smokers found that their mean starting age was 12 5 years old Find the 90 confidence interval of the mean Do not round in between steps Round answers to at least 3 decimal places Give your answers as decimals to two places

Use the given values to find the margin of error for a 85 confidence interval 71 9 o 7 8 n 99

You measure 42 backpacks weights and find they have a mean weight of 41 ounces Assume the population standard deviation is 2 1 ounces Based on this what is the margin of error associated with a 95 confidence interval for the true population mean backpack weight Give your answer as a decimal to two places The margin of error is ounces

typing speed The stem and leaf display below shows the results for the most recent clients 19 of whom received a job offer and 18 of whom did not Answer the questions that follow Typing speeds words per minute Offer No offer 72 3679 987653 99752210 Offer No offer 4 002 5668 5 003679 420 6 26 Key 322 3 6 36 a What were the ranges of typing speeds for the two groups 8 b Which group had the higher median typing speed Offer O No offer OThe medians were the same c Which group had more typing speeds in the 40s OOffer O No offer OEach had the same X