Statistics Questions and Answers

Part 4 7 Part 5 of 7 e State a conclusion There Choose one is is not enough evidence to conclude that the mean price in 2019 differs from the mean price in 2015

Kiana categorized her spending for this month into four categories Rent Food Fun and Other The percents she spent in each category are pictured here Food 23 Other 33 Rent 29 Fun 15 If Kiana spent a total of 2900 this month how much did she spend on Rent

House prices Data from the Denver Metro Ass dollars A random sample of 81 homes sold in 2 mean price in 2018 Assume the population star calculator

c Find the P value Round the P value 0 119

The city of Raleigh has 11 900 registered voters There are two candidates for city council in an upcoming election Brown and Feliz The day before the election a telephone poll of 350 randomly selected registered voters was conducted 114 said they d vote for Brown 216 said they d vote for Feliz and 20 were undecided Use this information from the sample to complete the following statements about the population of all registered voters in Raleigh Round your answers to the nearest person of the 11 900 registered voters to vote for Brown of the 11 900 registered voters to vote for Feliz Based on this sample we could expect Based on this sample we could expect Based on this sample of the 11 900 registered voters are still undecided

Number of People 978 5 4 3 1 16 20 Quortion Help 21 25 26 30 31 35 Age Q A frisbee golf club recorded the ages of its members and used the results to construct this graph Find the number of members 30 years of age or younger Video 1 Video 2 Message instructor

Callbrating a scale Making sure that the scales used by businesses in the United States a responsibility of the National Institute for Standards and Technology NIST in Washington technicians are testing a scale by using a weight known to weigh exactly 1000 grams The s reading is known to be a 2 4 They weigh this weight on the scale 50 times and read the readings have a sample mean of x 999 6 grams The calibration point is set too low if the han 1000 grams The technicians want to perform a hypothesis test to determine whether ow Use the a 0 10 level of significance and the P value method with the TI 84 Plus calcu Part 1 of 5 a State the appropriate null and alternate hypotheses Ho 1000 H 1000 This hypothesis test is a left tailed V test Part 1 5 Part 2 of 5 b Compute the value of the test statistic Round the answer to two decimal places

The line graph below shows the number of times Maria drove her car each day of the week LU 9 8 7 6 5 4 32 1 2 3 4 5 6 7 2 Day of Week How many times did Maria drive her car on day 4

apters 9 07 Calculate the gross pay of Alice a corn picker assuming she picked 4 150 ears of corn Note Round your final answer to the nearest cent Corn Picked 1 2 000 2 001 3 000 Over 3 000 Gross pay Rate per ear 0 04 per ear 0 05 per ear 0 09 per ear

Rodney is a shoe salesman for More Company He is paid 12 60 per hour plus a commission of 3 on all sales For the week assuming Rodney works 30 hours and has sales of 2 400 what is his gross pay Gross pay

The table below shows scores on a Math test 80 80 50 80 80 30 90 60 80 50 90 100 60 70 60 60 100 50 100 60 50 50 Complete the frequency table for the Math test scores Frequency Score 30 40 50 60 70 80 90 50 80 100 loccage instructor

Ages 15 18 19 22 23 26 27 30 31 34 Number of students 4 3 6 8 6 2 Relative Frequency de de 11 1 de de 35 38 Give your answers as a percents rounded to one decimal place Question Help Video Message instructor

2 The following is a data set of the average weekly number of cups of coffee consumed by employees in an office Find the mean and median and determine if the mean or median is the better measure of central tendency 8 9 6 0 5 6 3 36 1 4 3 5 2 3 1 4 Select the correct answer below Mean 6 Median 4 The median is the better measure of central tendency Mean 4 Median 6 The mean is the better measure of central tendency Mean 6 Median 4 The mean is the better measure of central tendency Mean 4 Median 6 The median is the better measure of central tendencv 2 12 30 PM

The city of Raleigh has 11 600 registered voters There are two candidates for city council in an upcoming election Brown and Feliz The day before the election a telephone poll of 550 randomly selected registered voters was conducted 297 said they d vote for Brown 227 said they d vote for Feliz and 26 were undecided Give the sample statistic for the percentage of voters surveyed who said they d vote for Brown Round your answer to the nearest tenth of a percent of the surveyed voters said they d vote for Brown This sample statistic suggests that we might expect Brown Round your answer to the nearest person Question Help Video Message instructor of the 11 600 registered voters to vote for

The city of Raleigh has 8500 registered voters There are two candidates for city council in an upcoming election Brown and Feliz The day before the election a telephone poll of 350 randomly selected registered voters was conducted 136 said they d vote for Brown 179 said they d vote for Feliz and 35 were undecided Describe the population the surveyors are really interested in All citizens of Raleigh All registered voters in Raleigh All registered voters with telephones in Raleigh The 350 voters surveyed The 136 voters who said they d vote for Brown None of the above

Describe the shape of the given histogram Select the correct answer below uniform Frequency 086420 10 0 2 4 6 8 10 12 14 16

Describe the shape of the given histogram 10 Frequency 86420 0 2 4 6 8 10 12 14 16 Select the correct answer below

A professor wants to estimate how many hours per w Construct a 90 confidence interval for the mean nu hours per week Round to two decimal places Answer

Are you smarter than a second grader A random sample of 61 second graders in a certain school district are given a standardized mathematics skills test The sample mean score is x 45 Assume the standard deviation of test scores is a 20 The nationwide average score on this test is 50 The school superintendent wants to know whether the second graders in her school district have weaker math skills than the nationwide average Use the a 0 01 level of significance and the P value method with the TI 84 Plus calculator Part 1 of 5 a State the appropriate null and alternate hypotheses Ho dt 30 H 50 This hypothesis test is a left tailed Part 1 5 Part 2 of 5 test b Compute the value of the test statistic Round the answer to two decimal places

Value 2 3 4 6 7 8 9 10 11 12 Frequency 3 4 6 3 2 3 4 4 4 2

QUESTION 6 1 POINT A small startup company wishes to know how many hours per week that its employees spend commuting to and from work The number of hours for each employee are shown below Construct a frequency table for grouped data using four classes 17 2 19 14 13 21 21 9 17 10 3 12 15 10 15 8 5 21 17 13 Provide your answer below

Age Frequency Relative Frequency 17 18 19 20 21 22 6 9 13 4 4 14

Question 9 of 10 3 points Question Attempt 3 of 3 Internet service An Internet service provider sampled 555 previous month

Listed below are the overhead widths in cm of seals measured from photographs and the weights in kg of the seals Find the value of the linear correlation coefficient r and find the critical values of r using a 0 05 Is there sufficient evidence to conclude that there is a linear correlation between overhead widths of seals from photographs and the weights of the seals Overhead Width Weight Click here to view a table of critical values for the correlation coefficient 7 1 115 7 8 9 9 188 251 The linear correlation coefficient is r Round to three decimal places as needed 9 3 201 8 8 201 8 1 179 Because the absolute value of the linear correlation coefficient is than the critical value there sufficient evidence to support the claim that there is a linear correlation between overhead widths of seals from photographs and the weights of the seals for a significance level of 0 05

For the following data calculate the correlation coefficient r and make a conclusion about the type of correlation The ages in years of 6 children and the number of words in their vocabulary Age x 1 3 4 5 Vocabulary size y 500 1350 1450 2200 2 1000 The correlation coefficient r is Round to three decimal places as needed Which of the following best describes the type of correlation that exists between age and vocabulary size O A Strong negative linear correlation OB Strong positive linear correlation OC No linear correlation 6 2250 OD Weak negative linear correlation OE Weak positive linear correlation

The data show systolic and diastolic blood pressure of certain people Find the regression equation letting the systolic reading be the independent x variable Find the best predicted diastolic pressure for a person with a systolic reading of 150 Use a significance level of 0 05 139 136 118 145 133 141 138 139 82 74 104 79 74 74 101 61 Click the icon to view the critical values of the Pearson correlation coefficient r Systolic Diastolic What is the regression equation y x Round to two decimal places as needed What is the best predicted diastolic pressure for a person with a systolic reading of 150 The best predicted diastolic pressure for a person with a systolic reading of 150 is Round to one decimal place as needed

Use the value of the linear correlation coefficient r to find the coefficient of determination and the percentage of the total variation that can be explained by the linear relationship between the two variables r 0 896 TE What is the value of the coefficient of determination r 0 8028 Round to four decimal places as needed What is the percentage of the total variation that can be explained by the linear relationship between the two variables Explained variation Round to two decimal places as needed

Listed below are systolic blood pressure measurements in mm Hg obtained from the same woman Find the regression equation letting the right arm blood pressure be the predictor variable Find the best predicted systolic blood pressure in the left arm given that the systolic blood pressure in the right arm is 95 mm Hg Use a significance level of 0 05 Right Arm 101 100 94 77 Left Arm 174 167 145 141 Click the icon to view the critical values of the Pearson correlation coefficient r The regression equation is y x X Round to one decimal place as needed 76 143

A real number between 0 and 6 will be picked according to the probability distribution shown in the figure Regions under the curve are labeled with A B C and D The area of each region is shown in the table 0 A 2 B 3 4 ID 5 6 7 a Find the probability that a real number between 2 and 5 is picked 0 Region A B b Find the probability that a real number between 4 and 6 is picked 0 C D Area Use the figure and the table to answer the parts below 0 30 0 50 0 15 0 05 Aa

Espanol Here are the fuel efficiencies in mpg of 10 new cars 28 25 33 20 17 47 44 17 51 38 What is the percentage of these cars with a fuel efficiency less than 28 mpg

There are 18 students in a certain painting class Their ages are shown below Complete the grouped relative frequency distribution for the data Note that we are using a class width of 6 Write each relative frequency as a decimal rounded to the nearest hundredth not as a percentage 30 30 26 21 Age 34 32 22 28 19 15 31 24 17 23 33 27 38 20 Age 15 to 20 21 to 26 27 to 32 33 to 38 Relative frequency 1 X

Let X denote the amount of time a book on two hour reserve is actually checked out and suppose the cdf is the following x 0 0 x 5 5 x F x 0 25 1 Use the cdf to obtain the following If necessary round your answer to four decimal places a Calculate P X 2 b Calculate P 1 5 x 2 c Calculate P X 2 5 d What is the median checkout duration solve 0 5 F M f Calculate E X e Obtain the density function f x f x F x g Calculate V X and V X 0 x 5 otherwise h If the borrower is charged an amount h x x when checkout duration is X compute the expected charge E h X

Internet service An Internet service provider sampled 540 customers and found that 76 of them experienced Interruption in high speed service during the previous month Part 1 of 3 a Find a point estimate for the population of all customers who experienced an interruption Round the answ at least three decimal places The point estimate for the population proportion of all customers who experienced an interruption is 0 141 Part 2 of 3 b Construct a 98 confidence interval for the proportion of all customers who experienced an interruption the answer to at least three decimal places A 98 confidence interval for the proportion of all customers who experienced an interruption is 0 106 p 0 176 Part 2 3 0 Part 3 of 3 c The company s quality control manager claims that no less than 18 of its customers experienced an interruption during the previous month Does the confidence interval contradict this claim Explain because all of the values in the confidence interval are Choose one Choose one 0 18 und

Question 7 of 10 2 points Question Attempt 2 of 3 Sound it out Phonics is an instructional method in which ch who were learning English were asked to identify as many le was 34 06 with a standard deviation of 23 33 Part 1 of 2 a Construct a 99 5 confidence interval for the mean r places

In a sample of 514 women who worked at home 158 were college graduates Worked at home were college graduates a Find a point estimate for the proportion of college graduates among women who work at home Round the answer to at least three decimal places Green that A 514 xx X 158 The pount estimate cs P X 158 10 307 514 b Verify requirements assumptions for finding a confidence interval about p c Construct an 80 confidence interval for the proportion of women who work at home who are college graduates Round the answer to at least three decimal places 20 20 X 1 0 80 1 2 0 10 0 307 0 020 1 0 280918 00 1 282 using 2 table 50 I 0 281kp Q 281 44 03 2 20 10 0 Confidence interval for the proporti PI x 2 X PXC1 P 0 307 1 282 X 10 307 XC1 0 307 514 d Based on the confidence interval is it reasonable to believe that the proportion of college graduates among women who work at home is the same as the proportion of college graduates among men who work at home Explain Hint How many men work at home that are college graduates

Sleeping outlier A simple random sample of ten coll 8 6 5 9 8 5 7 5 6 8 5

0 Gasoline Prices Suppose that States is 3 73 and in Russia it is 3 40 Assume these averages are the population means in the two countries and that the probability distributions are normally distrib uted with a standard deviation of 25 in the United States and a standard deviation of 20 in Russia a What is the probability that a randomly selected gas station in the United States charges less than 3 50 per gallon b What percentage of the gas stations in Russia charge less than 3 50 per gallon c What is the probability that a randomly selected gas station in Russia charged more than the mean price in the United States

1 As a potential worldwide pandemic avian serious health risk As of January 24 2014 there have been 694 human cases of this virus in the world Of these cases 402 have resulted in death Source www who int csr disease avian influenza en Consider the outcomes of these cases as a random sample of all possible outcomes a Find a point estimate for the proportion of people who would die if infected with the bird flu b Verify that the requirements for constructing a confidence interval about are satisfied c Construct a 90 confidence interval for the proportion of cases that would be expected to result in death if a pandemic occurred Round answers to two decimal places d Interpret the confidence interval e Construct a 95 confidence interval for the proportion of people who would die if infected with the bird flu Round answers to two decimal places ring the level of confidence has on the margin of error

2 Nitrates are groundwater contaminants derived from fertilizer septic tank see sewage Nitrate poisoning is particularly hazardous to infants under the age of 6 months The Maximum Contaminant Level MCL is the highest level of a contaminant the government allows in drinking water For nitrates the MCL is 10 mg L The health department wants to know what proportion of wells in Madison County that have nitrate levels above the MCL A worker has been assigned to take a simple random sample of wells in the county measure the nitrate levels and assess compliance What size sample should the health department obtain if the estimate is desired to be within 2 percent with 95 confidence if a there is no prior information available Round answers to two decimal places d two years ago showed that approximately 7 of the wells in Madison County

The percentage of citizens who have trust in newspapers declined approximately linearly from 37 in 2004 to 23 in 2006 Find the average rate of change per year of the percentage of citizens who have trust in newspapers The average rate of change per year of the percentage of citizens who have trust in newspapers was Type an integer or decimal rounded to two decimal places as needed

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Evaluate the following formula for p p 0 x 69 x 20 n 305 n 291 p 2 11 Z X2 n Z X X n n P P P P 3 p 1 and q 1 p paq paq n 7 Round to two decimal places as needed X1 n

P1 91 Evaluate E z P2 92 for z 1 645 n 2927 n 7833 P 0 010 M n A A 0 9894 0 0017 and 0 9983 E Round to four decimal places as needed

Evaluate E Z 01 02 n n for z 0 63 0 0 81 0 0 67 n 12 and n 48 Round to two decimal places as needed

Evaluate E t n for t 0 22 sp 43 47 n 48 and n 42 n E Round to two decimal places as needed

Listed in the accompanying table are heights in of mothers and their first daughters The data pairs are from a journal kept by Francis Galton Use the listed paired sample data and assume that the samples are simple random samples and that the differences have a distribution that is approximately normal Use a 0 01 significance level to test the claim that there is no difference in heights between mothers and their first daughters www Mother 61 0 62 5 60 0 64 0 65 0 63 0 Daughter 63 5 63 5 60 0 68 0 67 0 63 0 In this example d is the mean value of the differences d for the population of all pairs of data where each individual difference d is defined as the daughter s height minus the mother s height What are the null and alternative hypotheses for the hypothesis test Ho Pd in H Hd in Type integers or decimals Do not round Identify the P value P value Round to three decimal places as needed What is the conclusion based on the hypothesis test Since the P value is the significance level the null hypothesis There sufficient evidence to warrant rejection of the claim that there is no difference in heights between mothers and their first daughters

A rainstorm in Portland Oregon has wiped out the electricity in about 5 of the households in the city A management team in Portland has a big meeting tomorrow and all 6 members of the team are hard at work in their separate households preparing their presentations What is the probability that none of them has lost electricity in his her household Assume that their locations are spread out so that loss of electricity is independent among their households Round your response to at least three decimal places If necessary consult a list of formulas

A poll of 1079 Americans showed that 47 5 of the respondents prefer to watch the news rather than read or listen to it Use those results with a 0 10 significance level to test the claim that fewer than half of Americans prefer to watch the news rather than read or listen to it Use the P value method Use the normal distribution as an approximation to the binomial distribution Let p denote the population proportion of all Americans who prefer to watch the news rather than read or listen to it Identify the null and alternative hypotheses Ho P H P Type integers or decimals Do not round

5 In a particular geographic region the number of marriages per month over a 6 month period was as follows Jan 15 Feb 22 March 16 April 10 May 12 and June 20 5 marks Use this information to i construct a table Create your table here ii construct a line graph which accurately displays the data on a separate sheet of

Questic Determine whether each statement is true or false The probability that an event happens at least once A This statement is false The probability that