Slide 18 - 1 Copyright © 2009 Pearson Education, Inc. Active Learning Lecture Slides For use with Classroom Response Systems Intro Stats Third Edition.

Slide 18 - 1Copyright © 2009 Pearson Education, Inc.

Active Learning Lecture Slides For use with Classroom Response Systems

Intro Stats Third Edition

by De Veaux, Velleman, Bock

Chapter 18: Sampling Distribution Models


A certain population is approximately normal. We want to estimate its mean, so we will collect a sample. Which should be true if we use a large sample rather than a small one?I. The distribution of our sample data will be

approximately normal.II. The sampling distribution of the sample means will be

approximately normal.III. The variability of the sample means will be smaller.

A. I only

B. II only

C. III only

D. II and III

E. I, II, and III


A certain population is approximately normal. We want to estimate its mean, so we will collect a sample. Which should be true if we use a large sample rather than a small one?I. The distribution of our sample data will be

approximately normal.II. The sampling distribution of the sample means will be

approximately normal.III. The variability of the sample means will be smaller.

A. I only

B. II only

C. III only

D. II and III

E. I, II, and III


Which of the following is not an assumption or condition that needs to be checked for the one-proportion z-test?

A. Independence

B. Randomization

C. 10% Condition

D. Success/Failure Condition

E. Nearly Normal Condition


Which of the following is not an assumption or condition that needs to be checked for the one-proportion z-test?

A. Independence

B. Randomization

C. 10% Condition

D. Success/Failure Condition

E. Nearly Normal Condition


A certain population is strongly skewed to the right. We want to estimate its mean, so we will collect a sample. Which should be true if we use a large sample rather than a small one?

I. The distribution of our sample data will be closer to normal.

II. The sampling model of the sample means will be closer to normal.

III. The variability of the sample means will be greater.

A. I only

B. II only

C. III only

D. I and III only

E. II and III only


A certain population is strongly skewed to the right. We want to estimate its mean, so we will collect a sample. Which should be true if we use a large sample rather than a small one?

I. The distribution of our sample data will be closer to normal.

II. The sampling model of the sample means will be closer to normal.

III. The variability of the sample means will be greater.

A. I only

B. II only

C. III only

D. I and III only

E. II and III only


It is generally believed that electrical problems affect about 14% of new cars. An automobile mechanic conducts diagnostic tests on 128 new cars on the lot. How many successes (electrical failures) do you expect?

A. 1.28

B. 17.92

C. 110.08

D. Cannot determine from information given.


It is generally believed that electrical problems affect about 14% of new cars. An automobile mechanic conducts diagnostic tests on 128 new cars on the lot. How many successes (electrical failures) do you expect?

A. 1.28

B. 17.92

C. 110.08

D. Cannot determine from information given.





Chapter 19: Confidence Intervals for Proportions


The higher the level of confidence we want, the narrower our confidence interval becomes.

A. True

B. False


The higher the level of confidence we want, the narrower our confidence interval becomes.

A. True

B. False


The Success/Failure Condition states that we must expect at least ____ “successes” and ____ “failures.”

A. 5

B. 10

C. 15

D. 25


The Success/Failure Condition states that we must expect at least ____ “successes” and ____ “failures.”

A. 5

B. 10

C. 15

D. 25


We have calculated a 95% confidence interval and would prefer for our next confidence interval to have a smaller margin of error without losing any confidence. In order to do this, we can

I. change the z∗ value to a smaller number.II. take a larger sample.III. take a smaller sample.

A. I only

B. II only

C. III only

D. I and II

E. I and III


We have calculated a 95% confidence interval and would prefer for our next confidence interval to have a smaller margin of error without losing any confidence. In order to do this, we can

I. change the z∗ value to a smaller number.II. take a larger sample.III. take a smaller sample.

A. I only

B. II only

C. III only

D. I and II

E. I and III





Chapter 20: Testing Hypotheses About Proportions


A P-value indicates

A. the probability that the null hypothesis is true.

B. the probability that the alternative hypothesis is true.

C. the probability of the observed statistic given that the null hypothesis is true.

D. the probability of the observed statistic given that the alternative hypothesis is true.


A P-value indicates

A. the probability that the null hypothesis is true.

B. the probability that the alternative hypothesis is true.

C. the probability of the observed statistic given that the null hypothesis is true.

D. the probability of the observed statistic given that the alternative hypothesis is true.


A small P-value indicates either that the observation is improbable or that the probability calculation was based on incorrect assumptions.

A. True

B. False


A small P-value indicates either that the observation is improbable or that the probability calculation was based on incorrect assumptions.

A. True

B. False


In a hypothesis test, the null hypothesis represents the status quo.

A. True

B. False


In a hypothesis test, the null hypothesis represents the status quo.

A. True

B. False


According to a June 2004 Gallup poll, 28% of Americans “said there have been times in the last year when they haven’t been able to afford medical care.” Is this proportion higher for black Americans than for all Americans? In a random sample of 801 black Americans, 38% reported that there had been times in the last year when they had not been able to afford medical care. Which type of hypothesis test would you use?

A. One-tail upper tail

B. One-tail lower tail

C. Two-tail

D. Both A and B


According to a June 2004 Gallup poll, 28% of Americans “said there have been times in the last year when they haven’t been able to afford medical care.” Is this proportion higher for black Americans than for all Americans? In a random sample of 801 black Americans, 38% reported that there had been times in the last year when they had not been able to afford medical care. Which type of hypothesis test would you use?

A. One-tail upper tail

B. One-tail lower tail

C. Two-tail

D. Both A and B


A statistics professor wants to see if more than 80% of her students enjoyed taking her class. At the end of the term, she takes a random sample of students from her large class and asks, in an anonymous survey, if the students enjoyed taking her class. Which set of hypotheses should she test?

A. H0: p < 0.80 HA: p > 0.80

B. H0: p = 0.80 HA: p > 0.80

C. H0: p > 0.80 HA: p = 0.80

D. H0: p = 0.80 HA: p < 0.80


A statistics professor wants to see if more than 80% of her students enjoyed taking her class. At the end of the term, she takes a random sample of students from her large class and asks, in an anonymous survey, if the students enjoyed taking her class. Which set of hypotheses should she test?

A. H0: p < 0.80 HA: p > 0.80

B. H0: p = 0.80 HA: p > 0.80

C. H0: p > 0.80 HA: p = 0.80

D. H0: p = 0.80 HA: p < 0.80





Chapter 22: Comparing Two Proportions


When testing the difference between two proportions, we need to check the Success/Failure Condition. Which of the following is true?I. If only the smaller sample passes the Success/Failure Condition, we

can proceed with the test.

II. If only the larger sample passes the Success/Failure Condition, we can proceed with the test.

III. Both samples must pass the Success/Failure Condition to proceed with the test.

A. I only

B. II only

C. III only

D. None of the above.


When testing the difference between two proportions, we need to check the Success/Failure Condition. Which of the following is true?

I. If only the smaller sample passes the Success/Failure Condition, we can proceed with the test.

II. If only the larger sample passes the Success/Failure Condition, we can proceed with the test.

III. Both samples must pass the Success/Failure Condition to proceed with the test.

A. I only

B. II only

C. III only

D. None of the above.





Chapter 23: Inferences About Means


Which of the following is not an assumption or condition that needs to be checked for a one-sample t-test done on a sample drawn without replacement?

A. Randomization

B. 10% Condition

C. Success/Failure Condition

D. Nearly Normal Condition


Which of the following is not an assumption or condition that needs to be checked for a one-sample t-test done on a sample drawn without replacement?

A. Randomization

B. 10% Condition

C. Success/Failure Condition

D. Nearly Normal Condition


Which statement correctly compares t-distributions to the normal distribution?

I. t distributions are also mound shaped and symmetric.

II. t distributions have less spread than the normal distribution.

III. As degrees of freedom increase, the variance of t-distributions becomes smaller.

A. I only

B. II only

C. I and II only

D. I and III only


Which statement correctly compares t-distributions to the normal distribution?

I. t distributions are also mound shaped and symmetric.

II. t distributions have less spread than the normal distribution.

III. As degrees of freedom increase, the variance of t-distributions becomes smaller.

A. I only

B. II only

C. I and II only

D. I and III only


Which of the following is true aboutStudent’s t-models?

A. They are unimodal, symmetric, and bell shaped.

B. They have fatter tails than the Normal model.

C. As the degrees of freedom increase, the t-models look more and more like the Normal Model

D. All of the above.


Which of the following is true aboutStudent’s t-models?

A. They are unimodal, symmetric, and bell shaped.

B. They have fatter tails than the Normal model.

C. As the degrees of freedom increase, the t-models look more and more like the Normal Model

D. All of the above.


A researcher found that a 98% confidence intervalfor the mean hours per week spent studying bycollege students was (13, 17). Which is true?

A. There is a 98% chance that the mean hours per week spent studying by college students is between 13 and 17 hours.

B. We are 98% sure that the mean hours per week spent studying by college students is between 13 and 17 hours.

C. Students average between 13 and 17 hours per week studying on 98% of the weeks.

D. 98% of all students spend between 13 and 17 hours studying per week.


A researcher found that a 98% confidence intervalfor the mean hours per week spent studying bycollege students was (13, 17). Which is true?

A. There is a 98% chance that the mean hours per week spent studying by college students is between 13 and 17 hours.

B. We are 98% sure that the mean hours per week spent studying by college students is between 13 and 17 hours.

C. Students average between 13 and 17 hours per week studying on 98% of the weeks.

D. 98% of all students spend between 13 and 17 hours studying per week.


A philosophy professor wants to find out whether the mean age of the men in his large lecture class is equal to the mean age of the women in his class. After collecting data from his students, the professor tested the hypothesis against the alternative . The P-value for the test was 0.003. Which is true?

H0:

M-

W= 0

A. There is a 0.3% chance that the mean age for the men is equal to the mean age for the women.

B. There is a 0.3% chance that the mean age for the men is different from the mean age of the women.

C. It is very unlikely that the professor would see results like these if the mean age of men was equal to the mean age of women.

D. There is a 0.3% chance that another sample will give these same results.

A M WH : - 0


A philosophy professor wants to find out whether the mean age of the men in his large lecture class is equal to the mean age of the women in his class. After collecting data from his students, the professor tested the hypothesis against the alternative. The P-value for the test was 0.003. Which is true?

A. There is a 0.3% chance that the mean age for the men is equal to the mean age for the women.

B. There is a 0.3% chance that the mean age for the men is different from the mean age of the women.

C. It is very unlikely that the professor would see results like these if the mean age of men was equal to the mean age of women.

D. There is a 0.3% chance that another sample will give these same results.

H0:

M-

W= 0 HA

: M

- W

0


Doctors at a technology research facility randomly assigned equal numbers of people to use computer keyboards in two rooms. In one room a group of people typed a manuscript using standard keyboards, while in the other room people typed the same manuscript using ergonomic keyboards to see if those people could type more words per minute. After collecting data for several days the researchers tested the hypothesis against the one-tail alternative and found a P-value of 0.22. Which is true?

A) The people using ergonomic keyboards type 22% more words per minute.

B) There’s a 22% chance that people using ergonomic keyboards type more words per minute.

C) There’s a 22% chance that there’s really no difference in typing speed.

D) There’s a 22% chance another experiment will give these same results.

E) None of these.

H0:

1-

2= 0


Doctors at a technology research facility randomly assigned equal numbers of people to use computer keyboards in two rooms. In one room a group of people typed a manuscript using standard keyboards, while in the other room people typed the same manuscript using ergonomic keyboards to see if those people could type more words per minute. After collecting data for several days the researchers tested the hypothesis against the one-tail alternative and found a P-value of 0.22. Which is true?

A) The people using ergonomic keyboards type 22% more words per minute.

B) There’s a 22% chance that people using ergonomic keyboards type more words per minute.

C) There’s a 22% chance that there’s really no difference in typing speed.

D) There’s a 22% chance another experiment will give these same results.

E) None of these.

H0:

1-

2= 0


Trainers need to estimate the level of fat in athletes to ensure good health. Initial tests were based on a small sample but now the trainers double the sample size for a follow-up test. The main purpose of the larger sample is to…

A. reduce response bias.

B. reduce non-response bias.

C. decrease the variability in the population.

D. reduce confounding due to other variables.

E. decrease the standard deviation of the samplingmodel.


Trainers need to estimate the level of fat in athletes to ensure good health. Initial tests were based on a small sample but now the trainers double the sample size for a follow-up test. The main purpose of the larger sample is to…

A. reduce response bias.

B. reduce non-response bias.

C. decrease the variability in the population.

D. reduce confounding due to other variables.

E. decrease the standard deviation of the samplingmodel.

Slide 18 - 1 Copyright © 2009 Pearson Education, Inc. Active Learning Lecture Slides For use with Classroom Response Systems Intro Stats Third Edition.

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