Inference Review Multiple Choice Questions 1 2 3

Inference Review Multiple Choice Questions 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 Free Response Questions 36 37 38 39

Unit 5 MC Review #1 In a random sample of 1, 250 adult drivers, 450 said that they would cut their driving by 10 percent if this significantly helped the environment. Find a 95 percent confidence interval estimate of the proportion of adult drivers who are willing to cut their driving by 10 percent to help the environment. (Show all of “I” of “PANIC” as work. ) (. 333, . 387)

Unit 5 MC Review #1 In a random sample of 1, 250 adult drivers, 450 said that they would cut their driving by 10 percent if this significantly helped the environment. Find a 95 percent confidence interval estimate of the proportion of adult drivers who are willing to cut their driving by 10 percent to help the environment. (Show all of “I” of “PANIC” as work. ) (. 333, . 387)

Unit 5 MC Review #2 In general, how does doubling the sample size change the confidence interval size?

Unit 5 MC Review #2 In general, how does doubling the sample size change the confidence interval size?

Unit 5 MC Review #3 A 2007 survey of 980 American drivers concluded that 38 percent of the driving population would be willing to pay higher gas prices to protect the environment. What is meant by the poll having a margin of error of 3 percent? It is likely that between 35 percent and 41 percent of the driving population would be willing to pay higher gas prices to protect the environment.

Unit 5 MC Review #3 A 2007 survey of 980 American drivers concluded that 38 percent of the driving population would be willing to pay higher gas prices to protect the environment. What is meant by the poll having a margin of error of 3 percent? It is likely that between 35 percent and 41 percent of the driving population would be willing to pay higher gas prices to protect the environment.

Unit 5 MC Review #4

Unit 5 MC Review #4

Unit 5 MC Review #4

Unit 5 MC Review #5 There is insufficient information to answer this question.

Unit 5 MC Review #5 There is insufficient information to answer this question.

Unit 5 MC Review #6 A confidence interval estimate is determined from the summer earnings of an SRS of n students. All other things being equal, which of the following will result in a larger margin of error? I. A greater confidence level II. A larger sample standard deviation III. A larger sample size I and II are true, but III is not.

Unit 5 MC Review #6 A confidence interval estimate is determined from the summer earnings of an SRS of n students. All other things being equal, which of the following will result in a larger margin of error? I. A greater confidence level II. A larger sample standard deviation III. A larger sample size I and II are true, but III is not.

Unit 5 MC Review #7 Two confidence interval estimates from the sample are (72. 2, 77. 8) and (71. 3, 78. 7). One estimate is at the 95 percent level, and the other is at the 99 percent level. Which is which? (72. 2, 77. 8) is the 95 percent level. (71. 3, 78. 7) is the 99 percent level.

Unit 5 MC Review #7 Two confidence interval estimates from the sample are (72. 2, 77. 8) and (71. 3, 78. 7). One estimate is at the 95 percent level, and the other is at the 99 percent level. Which is which? (72. 2, 77. 8) is the 95 percent level. (71. 3, 78. 7) is the 99 percent level.

Unit 5 MC Review #8 An office manager believes that the percentage of employees arriving late is even greater than the previously claimed 7 percent. She conducts a hypothesis test on a random 200 employee arrivals and finds 23 punching in late. Is this strong evidence against the. 07 claim? Yes, because the P-value is 0. 0062

Unit 5 MC Review #8 An office manager believes that the percentage of employees arriving late is even greater than the previously claimed 7 percent. She conducts a hypothesis test on a random 200 employee arrivals and finds 23 punching in late. Is this strong evidence against the. 07 claim? Yes, because the P-value is 0. 0062

Unit 5 MC Review #9 Should there be more restrictions on handguns? In a 1995 pre-Columbine survey, 255 out of 1, 020 adults answered in the affirmative; in a 2000 post-Columbine survey, 352 out of 1, 100 answered affirmatively. Establish a 90 percent confidence interval estimate of the difference between the proportions of adults in 1995 and 2000 who support more restrictions on handguns. (Show all of “I” of “PANIC” as work. )

Unit 5 MC Review #9 Should there be more restrictions on handguns? In a 1995 pre-Columbine survey, 255 out of 1, 020 adults answered in the affirmative; in a 2000 post-Columbine survey, 352 out of 1, 100 answered affirmatively. Establish a 90 percent confidence interval estimate of the difference between the proportions of adults in 1995 and 2000 who support more restrictions on handguns. (Show all of “I” of “PANIC” as work. ) (-. 102, -. 038)

Unit 5 MC Review #10 The acceptance rate at a particular college is 58 percent. If one takes an SRS of applicants to this college and constructs a confidence interval estimate of the acceptance rate, which of the following would be true? I. The center of the interval would be 58 percent. II. The interval would contain 58 percent. III. A 99 percent confidence interval estimate would contain 58 percent. None on these are true.

Unit 5 MC Review #10 The acceptance rate at a particular college is 58 percent. If one takes an SRS of applicants to this college and constructs a confidence interval estimate of the acceptance rate, which of the following would be true? I. The center of the interval would be 58 percent. II. The interval would contain 58 percent. III. A 99 percent confidence interval estimate would contain 58 percent. None on these are true.

Unit 5 MC Review #11 Under what conditions would it be meaningful to construct a confidence interval estimate when the data consist of the entire population? It is never appropriate.

Unit 5 MC Review #11 Under what conditions would it be meaningful to construct a confidence interval estimate when the data consist of the entire population? It is never appropriate.

Unit 5 MC Review #12 A survey is to be taken to estimate the proportion of voters who favor stem cell research. What is the smallest sample size that will guarantee a margin of error of at most. 035 for a 96 percent confidence interval?

Unit 5 MC Review #12 A survey is to be taken to estimate the proportion of voters who favor stem cell research. What is the smallest sample size that will guarantee a margin of error of at most. 035 for a 96 percent confidence interval?

Unit 5 MC Review #13 Two 95 percent confidence interval estimates are obtained: I (78. 5, 84. 5) and II (80. 3, 88. 2). If the sample sizes are the same, which has the larger standard deviation? (80. 3, 88. 2) If the sample standard deviations are the same, which has the larger size? (78. 5, 84. 5)

Unit 5 MC Review #13 Two 95 percent confidence interval estimates are obtained: I (78. 5, 84. 5) and II (80. 3, 88. 2). If the sample sizes are the same, which has the larger standard deviation? (80. 3, 88. 2) If the sample standard deviations are the same, which has the larger size? (78. 5, 84. 5)

Unit 5 MC Review #14 In a random survey of 500 women, 315 said they would rather be poor and thin than rich and fat; in a random survey of 400 men, 220 said they would rather be poor and thin than rich and fat. Is there sufficient evidence to show that the proportion of women who would rather be poor and thin than rich and fat is greater than the proportion of men of who would rather be poor and thin than rich and fat? P-value of. 0075, so there is very strong evidence that the proportion of women is greater than that of men.

Unit 5 MC Review #14 In a random survey of 500 women, 315 said they would rather be poor and thin than rich and fat; in a random survey of 400 men, 220 said they would rather be poor and thin than rich and fat. Is there sufficient evidence to show that the proportion of women who would rather be poor and thin than rich and fat is greater than the proportion of men of who would rather be poor and thin than rich and fat? P-value of. 0075, so there is very strong evidence that the proportion of women is greater than that of men.

Unit 5 MC Review #15 A telephone survey of 400 registered voters showed that 256 had not yet made up their minds 1 month before the election. At what confidence level can we say that between 60 percent and 68 percent of the electorate were still undecided at that time. 90. 4 percent

Unit 5 MC Review #15 A telephone survey of 400 registered voters showed that 256 had not yet made up their minds 1 month before the election. At what confidence level can we say that between 60 percent and 68 percent of the electorate were still undecided at that time. 90. 4 percent

Unit 5 MC Review #16 94. 1 percent

Unit 5 MC Review #16 94. 1 percent

Unit 5 MC Review #17 The school superintendent wants to know what percentage of property owners are willing to support an increase in school taxes. What size sample should be obtained to determine with 90 percent confidence the support level to within 5 percent? 271

Unit 5 MC Review #17 The school superintendent wants to know what percentage of property owners are willing to support an increase in school taxes. What size sample should be obtained to determine with 90 percent confidence the support level to within 5 percent? 271

Unit 5 MC Review #18 Example of voluntary response bias, so the calculation is inappropriate

Unit 5 MC Review #18 Example of voluntary response bias, so the calculation is inappropriate

Unit 5 MC Review #19 How do sample size and confidence level influence the width of a confidence interval. Smaller samples result in wider intervals. Higher confidence also results in wider intervals.

Unit 5 MC Review #19 How do sample size and confidence level influence the width of a confidence interval. Smaller samples result in wider intervals. Higher confidence also results in wider intervals.

Unit 5 MC Review #20 In a well-known basketball study, it was reported that Larry Bird hit a second free throw in 48 out of 53 attempts after the first free throw was missed, and hit a second free throw in 251 of 285 attempts after the first free throw was made. Is there sufficient evidence to say that the probability that Bird will make a second free throw is different depending on whether or not he made the first free throw? P-value of. 10, so there is insufficient evidence that the probabilities are different.

Unit 5 MC Review #20 In a well-known basketball study, it was reported that Larry Bird hit a second free throw in 48 out of 53 attempts after the first free throw was missed, and hit a second free throw in 251 of 285 attempts after the first free throw was made. Is there sufficient evidence to say that the probability that Bird will make a second free throw is different depending on whether or not he made the first free throw? P-value of. 10, so there is insufficient evidence that the probabilities are different.

Unit 5 MC Review #21 There are 50, 000 high school students in an extended metropolitan region. As each of their students came in to register for classes, guidance counselors were instructed to use a calculator to pick a random number between 1 and 100. If the number 50 was picked, the student was included in a survey. For one of the many survey questions, 30 percent of the students said they couldn’t live without instant messaging. Are all conditions met for constructing a confidence interval of the proportion of this region’s teenagers who believe they couldn’t live without instant messaging? Yes, all conditions are met, and a confidence interval can be constructed.

Unit 5 MC Review #21 There are 50, 000 high school students in an extended metropolitan region. As each of their students came in to register for classes, guidance counselors were instructed to use a calculator to pick a random number between 1 and 100. If the number 50 was picked, the student was included in a survey. For one of the many survey questions, 30 percent of the students said they couldn’t live without instant messaging. Are all conditions met for constructing a confidence interval of the proportion of this region’s teenagers who believe they couldn’t live without instant messaging? Yes, all conditions are met, and a confidence interval can be constructed.

Unit 5 MC Review #22

Unit 5 MC Review #22

Unit 5 MC Review #23 Before televised debates, a poll of 800 registered voters showed 560 in favor of a particular candidate; after the debates a poll of 600 voters showed 450 in favor of the candidate. Is there sufficient evidence that the candidate’s popularity has increased-what is the test statistic?

Unit 5 MC Review #23 Before televised debates, a poll of 800 registered voters showed 560 in favor of a particular candidate; after the debates a poll of 600 voters showed 450 in favor of the candidate. Is there sufficient evidence that the candidate’s popularity has increased-what is the test statistic?

Unit 5 MC Review #24 A manufacturer of heart-lung machines periodically checks a sample of its product and performs a major recalibration if readings are sufficiently off target. Similarly, a rug factory periodically checks the sizes of its throw rugs coming off an assembly line and halts production if measurements are sufficiently off target. In both situations, we have the null hypothesis that the production equipment is performing satisfactorily. For each situation, which is the more serious concern, a Type I or Type II error? Machine producer: Type II error Carpet manufacturer: Type I error

Unit 5 MC Review #24 A manufacturer of heart-lung machines periodically checks a sample of its product and performs a major recalibration if readings are sufficiently off target. Similarly, a rug factory periodically checks the sizes of its throw rugs coming off an assembly line and halts production if measurements are sufficiently of target. In both situations, we have the null hypothesis that the production equipment is performing satisfactorily. For each situation, which is the more serious concern, a Type I or Type II error? Machine producer: Type II error Carpet manufacturer: Type I error

Unit 5 MC Review #25 We are interested in the proportion p of people who drive pick-up trucks in a large city. Seven percent of a simple random sample of 760 people say they drive pick-ups. What is the midpoint for a 99 percent confidence interval estimate of p? 0. 07

Unit 5 MC Review #25 We are interested in the proportion p of people who drive pick-up trucks in a large city. Seven percent of a simple random sample of 760 people say they drive pick-ups. What is the midpoint for a 99 percent confidence interval estimate of p? 0. 07

Unit 5 MC Review #26 A company negotiator claims that only 35 percent of union members will support a strike, but a union representative believes the true percentage is greater and runs a hypothesis test at the 5 percent significance level. If 57 out of an SRS of 150 union members say they are willing to strike, what is the test statistic?

Unit 5 MC Review #26 A company negotiator claims that only 35 percent of union members will support a strike, but a union representative believes the true percentage is greater and runs a hypothesis test at the 5 percent significance level. If 57 out of an SRS of 150 union members say they are willing to strike, what is the test statistic?

Unit 5 MC Review #27 If all variables remain constant, which of the following will increase the power of a hypothesis test? I. Increasing the sample size II. Increasing the significance level III. Increasing the probability of a Type II error I and II only

Unit 5 MC Review #27 If all variables remain constant, which of the following will increase the power of a hypothesis test? I. Increasing the sample size II. Increasing the significance level III. Increasing the probability of a Type II error I and II only

Unit 5 MC Review #28 Given that the power of a significance test against a particular alternative is 96 percent, what does 4 percent represent? The probability of mistakenly failing to reject a false null hypothesis is 4%.

Unit 5 MC Review #28 Given that the power of a significance test against a particular alternative is 96 percent, what does 4 percent represent? The probability of mistakenly failing to reject a false null hypothesis is 4%.

Unit 5 MC Review #29 We are 90% confident that the proportion of pet owners using herbicides who have pet with lymphomas is between 0. 342 and 0. 200 higher than the proportion of pet owners not using herbicides who have pets with lymphomas.

Unit 5 MC Review #29 We are 90% confident that the proportion of pet owners using herbicides who have pet with lymphomas is between 0. 342 and 0. 200 higher than the proportion of pet owners not using herbicides who have pets with lymphomas.

Unit 5 MC Review #30

Unit 5 MC Review #30

Unit 5 MC Review #31

Unit 5 MC Review #31

Unit 5 MC Review #32 A political action group wishes to learn the government approval rating on the environment. From a past study, they know that they will have to poll 270 people for their desired level of confidence. If they want to keep the same level of confidence but divide the margin of error in third, how many people will they have to poll? 2, 430 32 * 270 = 2, 430

Unit 5 MC Review #32 A political action group wishes to learn the government approval rating on the environment. From a past study, they know that they will have to poll 270 people for their desired level of confidence. If they want to keep the same level of confidence but divide the margin of error in third, how many people will they have to poll? 2, 430 32 * 270 = 2, 430

Unit 5 MC Review #33 Type I Error: produce a nonprofit able car; Type II Error: fail to produce a profitable car

Unit 5 MC Review #33 Type I Error: produce a nonprofit able car; Type II Error: fail to produce a profitable car

Unit 5 MC Review #34 Changing from a 95 percent confidence interval estimate for a population proportion to a 99 percent confidence interval estimate, with all other things being equal, how is the interval size affected? Increase the interval size by 31%

Unit 5 MC Review #34 Changing from a 95 percent confidence interval estimate for a population proportion to a 99 percent confidence interval estimate, with all other things being equal, how is the interval size affected? Increase the interval size by 31%

Unit 5 MC Review #35 Which of the following are true statements? T I. Tests of significance (hypothesis tests) are designed to measure the strength of evidence against the null hypothesis. F II. A well-planned test of significance should result in a statement either that the null hypothesis is true or that it is false. F III. The null hypothesis is one-sided and expressed using either < or > if there is interest in deviations in only one direction. F IV. It is helpful to examine your data before deciding whether to use a one-sided or a two-sided hypothesis test. F V. If the P-value is. 05, the probability that the null hypothesis is correct is. 05. F VI. The larger the P-value, the more evidence there is against the null hypothesis.

Unit 5 MC Review #35 Which of the following are true statements? F VII. The probability of a Type II error does not depend on the probability of a Type I error. F VIII. In conducting a hypothesis test, it is possible to simultaneously make both a Type I and Type II error. F IX. A Type II error will result if one incorrectly assumes the data are normally distributed. T X. The P-value of a test is the probability of obtaining a result as extreme as the one obtained assuming the null hypothesis is true. F XI. If the P-value for a test is. 043, the probability that the null hypothesis is true is. 043. F XII. When the null hypothesis is rejected, it is because it is not true.

Unit 5 MC Review #35 Which of the following are true statements? T XIII. If a population parameter is known, there is no reason to run a hypothesis test on that population parameter. F XIV. The P-value can be negative or positive depending upon whether the sample statistic is less than or greater than the claimed value of the population parameter in the null hypothesis. F XV. The P-value is based on a specific test statistic so must be chosen before an experiment is conducted. T XVI. The power of a test concerns its ability to detect an alternative hypothesis. T XVII. The significance level of a test is the probability of rejecting a true null hypothesis. F XVIII. The probability of a Type I error plus the probability of a Type II error always equals 1.

Unit 5 MC Review #35 Which of the following are true statements? T XIX. A P-value is a conditional probability. F XX. The P-value is the probability that the null hypothesis is true. F XXI. A P-value is the probability the null hypothesis is true given a particular observed statistic. F XXII. The significance level of a test is the probability of a Type II error. T XXIII. Given a particular alternative, the power of a test against that alternative is 1 minus the probability of the Type II error associated with that alternative. T XXIV. If the significance level remains fixed, increasing the sample size will reduce the probability of a Type II error.

Unit 5 MC Review #35 Which of the following are true statements? T XIX. A P-value is a conditional probability. F XX. The P-value is the probability that the null hypothesis is true. F XXI. A P-value is the probability the null hypothesis is true given a particular observed statistic. F XXII. The significance level of a test is the probability of a Type II error. T XXIII. Given a particular alternative, the power of a test against that alternative is 1 minus the probability of the Type II error associated with that alternative. T XXIV. If the significance level remains fixed, increasing the sample size will reduce the probability of a Type II error.

Unit 5 FR Review #36 An auto parts company advertises that its special oil additive will make the engine “run smoother, cleaner, longer, with fewer repairs. ” An independent laboratory decides to test part of this claim. It arranges to use a taxicab company’s fleet of cars. The cars are randomly divided into two groups. The company’s mechanics will use the additive in one group of cars but not in the other. At the end of a year the laboratory will compare the percentage of cars in each group that required engine repairs.

Unit 5 FR Review #36 An auto parts company advertises that its special oil additive will make the engine “run smoother, cleaner, longer, with fewer repairs. ” An independent laboratory decides to test part of this claim. It arranges to use a taxicab company’s fleet of cars. The cars are randomly divided into two groups. The company’s mechanics will use the additive in one group of cars but not in the other. At the end of a year the laboratory will compare the percentage of cars in each group that required engine repairs. a) What kind of a study is this?

Unit 5 FR Review #36 An auto parts company advertises that its special oil additive will make the engine “run smoother, cleaner, longer, with fewer repairs. ” An independent laboratory decides to test part of this claim. It arranges to use a taxicab company’s fleet of cars. The cars are randomly divided into two groups. The company’s mechanics will use the additive in one group of cars but not in the other. At the end of a year the laboratory will compare the percentage of cars in each group that requiredb)engine repairs. Will they do a one-tailed or a two-tailed test?

Unit 5 FR Review #36 An auto parts company advertises that its special oil additive will make the engine “run smoother, cleaner, longer, with fewer repairs. ” An independent laboratory decides to test part of this claim. It arranges to use a taxicab company’s fleet of cars. The cars are randomly divided into two groups. The company’s mechanics will use the additive in one group of cars but not in the other. At the end of a year the laboratory will compare the percentage of cars in each group that requiredc)engine repairs. Explain in this context what a Type I error would be.

Unit 5 FR Review #36 An auto parts company advertises that its special oil additive will make the engine “run smoother, cleaner, longer, with fewer repairs. ” An independent laboratory decides to test part of this claim. It arranges to use a taxicab company’s fleet of cars. The cars are randomly divided into two groups. The company’s mechanics will use the additive in one group of cars but not in the other. At the end of a year the laboratory will compare the percentage of cars in each group that requiredd)engine repairs. Explain in this context what a Type II error would be.

Unit 5 FR Review #36 An auto parts company advertises that its special oil additive will make the engine “run smoother, cleaner, longer, with fewer repairs. ” An independent laboratory decides to test part of this claim. It arranges to use a taxicab company’s fleet of cars. The cars are randomly divided into two groups. The company’s mechanics will use the additive in one group of cars but not in the other. At the end of a year the laboratory will compare the percentage of cars in each group that requirede)engine repairs. Which type of error would the additive manufacturer consider more serious?

Unit 5 FR Review #36 An auto parts company advertises that its special oil additive will make the engine “run smoother, cleaner, longer, with fewer repairs. ” An independent laboratory decides to test part of this claim. It arranges to use a taxicab company’s fleet of cars. The cars are randomly divided into two groups. The company’s mechanics will use the additive in one group of cars but not in the other. At the end of a year the laboratory will compare the percentage of cars in each group that required engine repairs. f) If the cabs with the additive do indeed run significantly better, can the company conclude it is an effect of the additive? Can they generalize this result and recommend the additive for all cars? Explain.

Unit 5 FR Review #36 An auto parts company advertises that its special oil additive will make the engine “run smoother, cleaner, longer, with fewer repairs. ” An independent laboratory decides to test part of this claim. It arranges to use a taxicab company’s fleet of cars. The cars are randomly divided into two groups. The company’s mechanics will use the additive in one group of cars but not in the other. At the end of a year the laboratory will compare the percentage of cars in each group that required engine repairs. f) If the cabs with the additive do indeed run significantly better, can the company conclude it is an effect of the additive? Can they generalize this result and recommend the additive for all cars? Explain.

Unit 5 FR Review #37 Among 242 Cleveland-area children born prematurely at low birth weights between 1977 and 1979, only 74% graduated from high school. Among a comparison group of 233 children of normal birth weight, 83% were high school graduates. (“Outcomes in Young Adulthood for Very-Low. Birth-Weight Infants, ” New England Journal of Medicine, 346, no. 3[2002])

Unit 5 FR Review #37 Among 242 Cleveland-area children born prematurely at low birth weights between 1977 and 1979, only 74% graduated from high school. Among a comparison group of 233 children of normal birth weight, 83% were high school graduates. (“Outcomes in Young Adulthood for Very-Low-Birth-Weight Infants, ” New England Journal of Medicine, 346, no. 3[2002]) a) Create a 95% confidence interval for the difference in graduation rates between children of normal and very low birth weights. Be sure to check the appropriate assumptions and conditions.

Unit 5 FR Review #37 Among 242 Cleveland-area children born prematurely at low birth weights between 1977 and 1979, only 74% graduated from high school. Among a comparison group of 233 children of normal birth weight, 83% were high school graduates. (“Outcomes in Young Adulthood for Very-Low-Birth-Weight Infants, ” New England Journal of Medicine, 346, no. 3[2002]) a) Create a 95% confidence interval for the difference in graduation rates between children of normal and very low birth weights. Be sure to check the appropriate assumptions and conditions. Sample values can be considered independent, because • • Randomization Condition: We have no reason to believe that the either the low or normal birth weight children are not representative of all children in those groups. The 10% Condition: The 242 is less than 10% of all low birth weight children and 233 is less than 10% of normal birth weight children.

Unit 5 FR Review #37 Among 242 Cleveland-area children born prematurely at low birth weights between 1977 and 1979, only 74% graduated from high school. Among a comparison group of 233 children of normal birth weight, 83% were high school graduates. (“Outcomes in Young Adulthood for Very-Low-Birth-Weight Infants, ” New England Journal of Medicine, 346, no. 3[2002]) a) Create a 95% confidence interval for the difference in graduation rates between children of normal and very low birth weights. Be sure to check the appropriate assumptions and conditions.

Unit 5 FR Review #37 Among 242 Cleveland-area children born prematurely at low birth weights between 1977 and 1979, only 74% graduated from high school. Among a comparison group of 233 children of normal birth weight, 83% were high school graduates. (“Outcomes in Young Adulthood for Very-Low-Birth-Weight Infants, ” New England Journal of Medicine, 346, no. 3[2002]) a) Create a 95% confidence interval for the difference in graduation rates between children of normal and very low birth weights. Be sure to check the appropriate assumptions and conditions. Since all conditions are satisfied, we will preform a -proportion z-interval. 2 . 03742 (. 0167, . 1633)

Unit 5 FR Review #37 Among 242 Cleveland-area children born prematurely at low birth weights between 1977 and 1979, only 74% graduated from high school. Among a comparison group of 233 children of normal birth weight, 83% were high school graduates. (“Outcomes in Young Adulthood for Very-Low-Birth-Weight Infants, ” New England Journal of Medicine, 346, no. 3[2002]) a) Create a 95% confidence interval for the difference in graduation rates between children of normal and very low birth weights. Be sure to check the appropriate assumptions and conditions. (. 0167, . 1633) We are 95% confident that between 1. 7% and 16. 3% more normal birth weight children graduated from high school than children who had a very low birth weight.

Unit 5 FR Review #37 Among 242 Cleveland-area children born prematurely at low birth weights between 1977 and 1979, only 74% graduated from high school. Among a comparison group of 233 children of normal birth weight, 83% were high school graduates. (“Outcomes in Young Adulthood for Very-Low-Birth-Weight Infants, ” New England Journal of Medicine, 346, no. 3[2002]) b) Does this provide evidence that premature birth may be a risk factor for not finishing high school? Use your confidence interval to test an appropriate hypothesis.

Unit 5 FR Review #37 Among 242 Cleveland-area children born prematurely at low birth weights between 1977 and 1979, only 74% graduated from high school. Among a comparison group of 233 children of normal birth weight, 83% were high school graduates. (“Outcomes in Young Adulthood for Very-Low-Birth-Weight Infants, ” New England Journal of Medicine, 346, no. 3[2002]) c) Suppose your conclusion is incorrect. Which type of error did you make? If children who had a very low birth weight do not have a lower high school graduation rate than children of normal birth weight, then we made a Type I error. We rejected a null hypothesis of “no difference” when we shouldn’t have.

Unit 5 FR Review #37 Among 242 Cleveland-area children born prematurely at low birth weights between 1977 and 1979, only 74% graduated from high school. Among a comparison group of 233 children of normal birth weight, 83% were high school graduates. (“Outcomes in Young Adulthood for Very-Low-Birth-Weight Infants, ” New England Journal of Medicine, 346, no. 3[2002]) c) Suppose your conclusion is incorrect. Which type of error did you make? If children who had a very low birth weight do not have a lower high school graduation rate than children of normal birth weight, then we made a Type I error. We rejected a null hypothesis of “no difference” when we shouldn’t have.

Unit 5 FR Review #38

Unit 5 FR Review #38 a) Why does the company use upper tail tests in this situation?

Unit 5 FR Review #38 b) Explain what Type I and Type II errors would represent in this context, and describe the risk that each error poses to the company.

Unit 5 FR Review #38 b) Explain what Type I and Type II errors would represent in this context, and describe the risk that each error poses to the company.

Unit 5 FR Review #38 c) The company is thinking of changing its test to use a 10% level of significance. How would this change the company’s exposure to each type of risk?

Unit 5 FR Review #38 c) The company is thinking of changing its test to use a 10% level of significance. How would this change the company’s exposure to each type of risk?

Unit 5 FR Review #39 The advertising company described in Question 38 is thinking about signing a WNBA star to an endorsement deal. In its poll 27% of the respondents could identify her.

Unit 5 FR Review #39 The advertising company described in Question 38 is thinking about signing a WNBA star to an endorsement deal. In its poll 27% of the respondents could identify her. a) Fans who never took Statistics can’t understand why the company did not offer this WNBA player an endorsement contract even though the 27% recognition rate in the poll is above the 25% threshold. Explain it to them.

Unit 5 FR Review #39 The advertising company described in Question 38 is thinking about signing a WNBA star to an endorsement deal. In its poll 27% of the respondents could identify her. b) Suppose that further polling reveals that this WNBA star really is known to about 30% of the target audience. Did the company initially commit a Type I or Type II error in not signing her?

Unit 5 FR Review #39 The advertising company described in Question 38 is thinking about signing a WNBA star to an endorsement deal. In its poll 27% of the respondents could identify her. c) Would the power of the company’s test have been higher or lower if the player were more famous? Explain.

Unit 5 FR Review #39 The advertising company described in Question 38 is thinking about signing a WNBA star to an endorsement deal. In its poll 27% of the respondents could identify her. c) Would the power of the company’s test have been higher or lower if the player were more famous? Explain.