Complete Test Bank Ch.15 T Test For Two Related Samples 11e

MULTIPLE‑CHOICE TEST ITEMS

CHAPTER 15

t TEST FOR TWO RELATED SAMPLES

15.1 Two samples are related if each observation in one sample is paired with

a) a subset of observations in the other sample.

b) a single observation in the other sample.

c) all observations in the other sample.

d) none of the observations in the other sample.

15.2 Which one of the following does not illustrate two related samples?

a) Identical twins are split into two groups.

b) Schoolchildren are measured before and after the school term.

c) Marital couples are split into two groups.

d) College freshmen are split into two groups.

15.3 Compared to the standard error for two independent samples, that for two related samples will tend to be

a) smaller.

b) the same.

c) approximately the same.

d) large.

15.4 The sample sizes for two related samples must be

a) very large.

b) not too small.

c) equal.

d) approximately equal.

15.5 Once pairs of observations have been converted to difference scores, the t test for two related samples can be viewed as a

a) z test for a single sample.

b) t test for a single sample.

c) t test for two independent samples.

d) t test for a population correlation coefficient.

15.6 When reporting the conclusion of a hypothesis test for two related samples, it's important to mention the

a) level of significance.

b) null hypothesis.

c) sample size.

d) repeated measures or matching procedure.

15.7 If two related samples each consists of 15 subjects, a 99 percent confidence interval will be based on degrees of freedom equal to

a) 13

b) 14

c) 15

d) 28

15.8 A confidence interval permits a single interpretation only when both of its limits

a) are positive.

b) are negative.

c) have similar signs.

d) include a value of zero.

15.9 Cohen's d for two related samples requires that the

a) mean difference be divided by the sample standard deviation of difference scores.

b) mean difference be divided by the population standard deviation of difference scores.

c) mean difference be divided by the estimated standard error.

d) none of the above.

15.10 Cohen's guidelines for values of d associated with small, medium, and large effects are

a) are different depending on whether two samples are independent or related.

b) are the same regardless of whether the two samples are independent or related.

c) depend on the level of significance.

d) depend on the sample sizes.

15.11 You need be concerned about the normality assumption for the t test two related samples only when sample

a) size is ten or less.

b) size is greater than ten.

c) variances are radically different.

d) sizes are different.

15.12 A shift in the unit of analysis from original observations, as in two independent samples, to the differences between pairs of original observations, as in two related samples, causes degrees of freedom to be

a) reduced by a factor of one-half.

b) increased by a factor of two.

c) maintained at the same value.

d) reduced by one.

15.13 Repeated measures usually cause an increase in

a) the observed mean difference.

b) the probability of retaining a true null hypothesis.

c) variability.

d) none of the above.

15.14 Using the same subject in both samples would most likely control for

a) situational differences.

b) individual differences.

c) measurement errors.

d) experimenter errors.

15.15 Avoid using the same subject in both groups if there is a possibility that subjects might

a) become bored.

b) drop out before completing the experiment.

c) contaminate experimental treatments.

d) differ considerably among themselves.

15.16 When subjects perform double duty in both conditions of an experiment, the order in which conditions are experienced should be

a) counterbalanced.

b) controlled.

c) randomized.

d) held constant.

15.17 The t test for two related samples should be used if

a) subjects are matched.

b) subjects are measured twice.

c) either a or b

d) sample sizes are equal.

15.18 The dream times were measured for each of twenty volunteers during two sleep periods: once after an evening when no alcohol was consumed and once after an evening when alcohol was consumed

To analyze the test results, use a t test for two related samples because

a) subjects are all young adults.

b) equal numbers of subjects participate in both periods.

c) the same subject is measured twice.

d) each subject is monitored for rapid eye movement.

15.19 The dream times for each of twenty volunteers are measured during two sleep periods: once after an evening when no alcohol was consumed and once after an evening when alcohol was consumed. It would be appropriate to test the null hypothesis with a

a) two‑tailed test at the .05 level of significance.

b) one‑tailed test, lower tail critical, at the .05 level of significance.

c) one‑tailed test, upper tail critical, at the .05 level of significance.

d) either a one‑ or two‑tailed test, but at the .001 level of significance.

15.20 The dream times for each of twenty volunteers are measured during two sleep periods: once after an evening when no alcohol was consumed and once after an evening when alcohol was consumed. It would be most important that subjects experience the two conditions in

a) the same order and on consecutive nights (before any alcohol effect disappears).

b) the same order and on nonconsecutive nights (after any alcohol effect disappears).

c) counterbalanced order and on consecutive nights (before any alcohol effect disappears).

d) counterbalanced order and on nonconsecutive nights (after any alcohol effect disappears).

15.21 The dream times for each of twenty volunteers are measured during two sleep periods: once after an evening when no alcohol was consumed and once after an evening when alcohol was consumed. If the results support the research hypothesis, it would be appropriate to conclude that alcohol consumption

a) could affect dreamtime.

b) could affect dreamtime when subjects are used as their own controls.

c) affects dreamtime.

d) affects dreamtime when subjects are used as their own controls.

15.22 A medical researcher compares the blood pressure readings for a group of high-risk patients both before and after the administration of a new tension-reducing drug. The appropriate test would be a

a) t test for one sample.

b) t test for two independent samples.

c) t test for two related samples.

d) none of the above

15.23 Grade-school children are randomly assigned to reading groups of either four or eight children throughout the school year. At the end of the school term, scores are obtained for each child on a standardized reading achievement test. The appropriate test (to evaluate any difference between reading group size) would be a

a) t test for one sample.

b) t test for two independent samples.

c) t test for two related samples.

d) none of the above

15.24 If a sample correlation coefficient qualifies as a rare outcome under the null hypothesis, then you can conclude that the

a) sample correlation coefficient differs from zero.

b) sample correlation coefficient could be zero.

c) population correlation coefficient could be zero.

d) population correlation coefficient differs from zero.

15.25 In the t test for a correlation coefficient, the difference between the sample correlation coefficient and zero is divided by the

a) sample size.

b) standard deviation.

c) standard error.

d) hypothesized population correlation coefficient.

15.26 For the t test for a correlation coefficient, the number of degrees of freedom equals

a) n + 1

b) n

c) n ‑ 1

d) n – 2

15.27 The t test for a correlation coefficient can be used only if

a) sample size is large.

b) the hypothesized population correlation coefficient equals zero.

c) the sample correlation coefficient deviates from zero.

d) degrees of freedom are large.