Suppose that the mean height in a population is 160 cm and that the standard deviation of height in that population is 10 cm; suppose also that heights in this population follow a normal distribution. Candidate X is 180 cm tall. What is the z-score that is associated with Candidate X's height in that population?

• A.-2
• B.0
• C.2
• D.10
• E.20

Suppose that the mean height in a population is 160 cm and that the standard deviation of height in that population is 10 cm; suppose also that heights in this population follow a normal distribution. Candidate Y is 160 cm tall. What is the z-score that is associated with Candidate Y's height in that population?

• A.-2
• B.0
• C.2
• D.20
• E.None of the above

Suppose that the mean height in a population is 160 cm and that the standard deviation of height in that population is 10 cm; suppose also that heights in this population follow a normal distribution. Candidate Z is 140 cm tall. What is the z-score that is associated with Candidate Z's height in that population?

• A.-2
• B.0
• C.2
• D.10
• E.20

Suppose that the mean height in a population is 160 cm and that the standard deviation of height in that population is 10 cm; suppose also that heights in this population follow a normal distribution. Regarding height in this population, a candidate who is 130 cm tall would be in which of the following ranges?

• A.less than the 2.5th percentile
• B.between the 2.5th percentile and the 97.5th percentile
• C.greater than the 97.5th percentile

Suppose that the mean height in a population is 160 cm and that the standard deviation of height in that population is 10 cm; suppose also that heights in this population follow a normal distribution. Regarding height in this population, a candidate who is 170 cm tall would be in which of the following ranges?

• A.less than the 2.5th percentile
• B.between the 2.5th percentile and the 97.5th percentile
• C.greater than the 97.5th percentile

Suppose that the mean height in a population is 160 cm and that the standard deviation of height in that population is 10 cm; suppose also that heights in this population follow a normal distribution. Regarding height in this population, a candidate who is 180 cm tall would be in which of the following ranges?

• A.less than the 2.5th percentile
• B.between the 2.5th percentile and the 97.5th percentile
• C.greater than the 97.5th percentile

Suppose that, for a set of responses from a sample, the mean is 10, the standard deviation is 3, and the sample size is 100. Which ONE of the following would be the corresponding standard error for the sample mean?

• A.0.03
• B.0.30
• C.3
• D.300

Suppose that, for a set of responses from two groups, for Group A, the mean is 10, the standard deviation is 3, and the sample size is 200, and, for Group B, the mean is 12, the standard deviation is 4, and the sample size is 220. Which ONE of the following would be the corresponding standard error for a test of the difference in means?

• A.0.11
• B.0.18
• C.0.34
• D.0.94

All else equal, adding participants to a study measuring support for the president should do what to the standard error for support for the president?

• A.reduce the standard error
• B.increase the standard error
• C.not change the standard error

Suppose that Researcher A has a study, and Researcher B has a study, and that both studies use participants randomly drawn from the same population. Both researchers are measuring support for the president on a 0-to-100 scale. Researcher A's standard error is 2, and Researcher B's standard error is 3. Which researcher has the more precise measurement of support for the president?

• A.Researcher A
• B.Researcher B
• C.There is not enough information to correctly answer this question.

Suppose that Researcher A is measuring support for the president on a 0-to-100 scale; the standard error for Researcher A's set of measurements is 8. But then Researcher A divides all measurements by 10 so that support for the president is on a 0-to-10 scale. Which ONE of the following is true about this?

• A.The standard error for the measurements on the 0-to-10 scale should be 8.
• B.The standard error for the measurements on the 0-to-10 scale should be less than 8.
• C.The standard error for the measurements on the 0-to-10 scale should be greater than 8.

All else equal, randomly losing data for half of the participants in a study measuring support for the president should do what to the standard error for support for the president?

• A.reduce the standard error
• B.increase the standard error
• C.not change the standard error

In a given sample of 400 persons, the mean support for the president is 60 with a standard deviation of 10. What is the t-statistic for the test of whether this mean of 60 differs from 50?

• A.0
• B.10
• C.20
• D.400

In a given sample of 1600 persons, the mean support for the president is 50 with a standard deviation of 10. Which of these could be the t-statistic for the test of whether this mean of 50 differs from 50?

• A.0
• B.10
• C.20
• D.400

In an experiment, the control group had 400 participants, and the mean response was a 6, with a standard deviation of 2; the treatment group had 400 participants, and the mean response was a 10, with a standard deviation of 4. Which of these could be the t-statistic for a test of whether the control mean differed from the treatment mean, to one decimal place?

• A.0
• B.17.9
• C.49.6
• D.80.0

In an experiment, the control group had 100 participants, and the mean response was a 10, with a standard deviation of 4; the treatment group had 100 participants, and the mean response was a 10, with a standard deviation of 6. Which of these could be the t-statistic for a test of whether the control mean differed from the treatment mean?

• A.0
• B.2
• C.4
• D.12

Reset Selection

In an experiment, the control group had 49 participants, and the mean response was a 6, with a standard deviation of 3; the treatment group had 49 participants, and the mean response was a 10, with a standard deviation of 4. Which of these could be the t-statistic for a test of whether the control mean differed from the treatment mean, to one decimal place?

• A.0
• B.2.3
• C.5.6
• D.7.8

In a given sample of 100 persons, the mean support for the president is 60 with a standard deviation of 5. What is the t-statistic for the test of whether this mean of 60 differs from 50?

• A.0
• B.5
• C.10
• D.20

Suppose that we conduct an experiment in which the control group is asked to rate their support for Candidate X on a 0-to-100 scale, and the treatment group is shown a campaign video and then asked to rate their support for Candidate X on a 0-to-100 scale. For the 100 participants in the control group, the mean rating is 50 and the standard deviation of the ratings is 10. For the 100 participants in the treatment group, the mean rating in the treatment group is 60 and the standard deviation is 12. Which of the following could be the t-statistic for that t-test, to two decimal places?

• A.-4.09
• B.-6.40
• C.-21.32
• D.-25.98

Generally speaking, as p-values get lower, the associated t-statistics ___.

• A.get lower
• B.get higher
• C.get closer to zero
• D.get farther from zero

Which ONE of these t-statistics would have the lowest associated p-value, all else equal?

• A.0
• B.-1
• C.2
• D.-4

Suppose that we conduct an experiment in which the control group is asked to rate their support for Candidate X on a 0-to-100 scale, and the treatment group is shown a campaign video and then asked to rate their support for Candidate X on a 0-to-100 scale. We then conduct a t-test to test the null hypothesis that the mean level of support for Candidate X in the control group does not differ from the mean level of support for Candidate X in the treatment group. If the sample size is sufficiently large and the t-statistic for this test is t=3.00, then which of the following should be done?

• A.the null hypothesis should be rejected and the alternative hypothesis should be accepted
• B.the null hypothesis should be accepted and the alternative hypothesis should be rejected
• C.Neither of the above

Suppose that we conduct an experiment in which the control group is asked to rate their support for Candidate X on a 0-to-100 scale, and the treatment group is shown a campaign video and then asked to rate their support for Candidate X on a 0-to-100 scale. We then conduct a t-test to test the null hypothesis that the mean level of support for Candidate X in the control group does not differ from the mean level of support for Candidate X in the treatment group. If the t-statistic for this test is t=0.03, then which of the following should be done?

• A.the null hypothesis should be rejected and the alternative hypothesis should be accepted
• B.the null hypothesis should be accepted and the alternative hypothesis should be rejected
• C.Neither of the above

Which of the following would be the t-statistic that corresponds to a p-value of 0.05, in sufficiently large samples?

• A.t=0.00
• B.t=0.05
• C.t=1.00
• D.t=1.96
• E.t=2.49

Suppose that researchers measured participant support for Candidate X, then showed participants a campaign video, and then once again measured participant support for Candidate X. The researchers than conducted a test for whether the mean level of support for Candidate X among participants before watching the video differed from the mean level of support for Candidate X among participants after watching the video. Of the following, the researchers should use ___.

• A.a paired t-test
• B.an unpaired t-test

Suppose that researchers conduct an experiment in which participants are randomly assigned to a control group or to a treatment group. Participants in the control group are asked to rate their support for Candidate X on a 0-to-100 scale, and participants in the treatment group are shown a campaign video and then asked to rate their support for Candidate X on a 0-to-100 scale. Of the following, the researchers should use ___ to test whether the mean level of support in the control group differs from the mean level of support in the treatment group.

• A.a paired t-test
• B.an unpaired t-test