Question 1

State the critical value(s)for a t test using a two-tailed test at a .05 level of significance: t(20).

Accepted Answer

A)  ±1.725 
B)  ±2.093 
C)  ±2.086 
D)  ±0.687

Question 2

A t test is associated with N degrees of freedom.

Accepted Answer

A) True 
 B)False

Question 3

A researcher reports a significant effect with t(14)= 3.24.Compute $\eta$2 for this result.

Accepted Answer

A)  $\eta$2 = 0.43 (large effect size) 
B)  $\eta$2 = 0.43 (medium effect size) 
C)  $\omega$2 = 0.37 (large effect size) 
D)  $\omega$2 = 0.37 (medium effect size)

Question 4

Which of the following is an assumption for computing any type of independent-sample t test?

Accepted Answer

A)  Data in the population being sampled are normally distributed. 
B)  Data were obtained from a sample that was selected using a random sampling procedure. 
C)  The probabilities of each measured outcome in a study are independent. 
D)  All of these.

Question 5

A researcher reports a significant mean difference in a given population.If she computes both $\eta$2 and $\omega$2 to measure the effect size,then which estimate will be most conservative?

Accepted Answer

A)  $\eta$2 
B)  $\omega$2 
C)  It depends on the sample size. 
D)  It depends on the value of the t statistic.

Question 6

The estimated standard error in the t statistic uses the ______ to estimate the ______ when the population variance is unknown.

Accepted Answer

A)  sample variance; population variance 
B)  population variance; sample variance 
C)  standard error; sample variance 
D)  degrees of freedom; sample size

Question 7

A researcher records the crying time (in minutes)of infants given oral administration of sucrose (n = 12)or tap water (n = 16)prior to a heel prick.The mean crying time in the sucrose group was 3.3 ± 2.4 (M ± SD)min; in the tap water group,it was 7.3 ± 1.6 (M ± SD)min.If the null hypothesis is that there is no difference in crying time,then what is the decision for this test?

Accepted Answer

A)  Crying time was significantly reduced among infants given the water solution prior to a heel prick. 
B)  Crying time was not reduced among infants given the sucrose solution prior to a heel prick. 
C)  Crying time was significantly reduced among infants given the sucrose solution prior to a heel prick. 
D)  Crying time was the same in both groups.

Question 8

An estimated Cohen's d is interpreted in terms of the number of standard deviations that an effect shifted in some population.

Accepted Answer

A) True 
 B)False

Question 9

A local elementary school determined that the average number of volunteers for their "Step into Spring" annual fundraiser has been 14 persons on average (per event).After taking additional measures to recruit volunteers this year,they got 28 people to volunteer.Test whether these additional measures increased the number of volunteers at a .05 level of significance.

Accepted Answer

A)  Yes, because the number of volunteers doubled; this is a significant increase. 
B)  No, this is not a significant increase because the error term is too large. 
C)  This would have been significant if it were a two-tailed test. 
D)  There is not enough information to answer this question.

Question 10

Which measure of effect size is most commonly reported with a t test?

Accepted Answer

A)  $\eta$2 
B)  $\omega$2 
C)  t statistic 
D)  Cohen's d

Question 11

A researcher reports that stress levels among nurses are higher compared to stress levels in the general population,t(20)= 2.086,p = .05 (d = .12).Was this a one-tailed or a two-tailed test?

Accepted Answer

A)  One-tailed test because the p value is equal to .05. 
B)  Two-tailed test because the p value is equal to .05. 
C)  It could be a one- or a two-tailed test.

Question 12

Cohen's d is a measure of proportion of variance.

Accepted Answer

A) True 
 B)False

Question 13

A researcher reports that the mean difference in the body weight of rats following a pharmacological versus control treatment is 14 g,with a pooled sample variance equal to 256.What is the effect size for this test using estimated Cohen's d?

Accepted Answer

A)  d = 0.06; small effect size 
B)  d = 0.08; small effect size 
C)  d = 0.88; large effect size 
D)  There is not enough information to answer this question.

Question 14

Measures of proportion of variance are computed the same for all t tests.

Accepted Answer

A) True 
 B)False

Question 15

The p value is reported with the test statistic of a one-sample and a two-independent-sample t test using APA format.

Accepted Answer

A) True 
 B)False

Question 16

When testing a hypothesis with one or two groups selected from a population with an unknown variance,a t test is appropriate.

Accepted Answer

A) True 
 B)False

Question 17

$\eta$2 is computed ______ for the one-sample and the two-independent-sample t tests.

Accepted Answer

A)  differently 
B)  infinitely 
C)  similarly 
D)  semantically

Question 18

State the critical value(s)for a t test using a .05 level of significance in the lower tail only: t(24).

Accepted Answer

A)  ±1.711 
B)  -1.711 
C)  ±2.064 
D)  -2.064

Question 19

Normality,random sampling,and independence are all assumptions for the one-sample t test.

Accepted Answer

A) True 
 B)False

Question 20

State the critical value(s)for the following two-tailed t test at a .05 level of significance: t($\infty$).

Accepted Answer

A)  ±1.645 
B)  ±1.96 
C)  the same as for a two-tailed z test at a .05 level of significance 
D)  ±1.96 and the same as for a two-tailed z test at a .05 level of significance

Exam 9: Testing Means: One-Sample and Two-Independent-Sample T Tests

State the critical value(s) for a t test using a two-tailed test at a .05 level of significance: t(20) .

A t test is associated with N degrees of freedom.

A researcher reports a significant effect with t(14) = 3.24.Compute $\eta$ ² for this result.

Which of the following is an assumption for computing any type of independent-sample t test?

A researcher reports a significant mean difference in a given population.If she computes both $\eta$ ² and $\omega$ ² to measure the effect size,then which estimate will be most conservative?

The estimated standard error in the t statistic uses the to estimate the when the population variance is unknown.

An estimated Cohen's d is interpreted in terms of the number of standard deviations that an effect shifted in some population.

Which measure of effect size is most commonly reported with a t test?

A researcher reports that stress levels among nurses are higher compared to stress levels in the general population,t(20) = 2.086,p = .05 (d = .12) .Was this a one-tailed or a two-tailed test?

Cohen's d is a measure of proportion of variance.

A researcher reports that the mean difference in the body weight of rats following a pharmacological versus control treatment is 14 g,with a pooled sample variance equal to 256.What is the effect size for this test using estimated Cohen's d?

Measures of proportion of variance are computed the same for all t tests.

The p value is reported with the test statistic of a one-sample and a two-independent-sample t test using APA format.

When testing a hypothesis with one or two groups selected from a population with an unknown variance,a t test is appropriate.

$\eta$ ² is computed ______ for the one-sample and the two-independent-sample t tests.

State the critical value(s) for a t test using a .05 level of significance in the lower tail only: t(24) .

Normality,random sampling,and independence are all assumptions for the one-sample t test.

State the critical value(s) for the following two-tailed t test at a .05 level of significance: t( $\infty$ ) .

Exam 9: Testing Means: One-Sample and Two-Independent-Sample T Tests

State the critical value(s) for a t test using a two-tailed test at a .05 level of significance: t(20) .

A t test is associated with N degrees of freedom.

A researcher reports a significant effect with t(14) = 3.24.Compute η\etaη 2 for this result.

Which of the following is an assumption for computing any type of independent-sample t test?

A researcher reports a significant mean difference in a given population.If she computes both η\etaη 2 and ω\omegaω 2 to measure the effect size,then which estimate will be most conservative?

The estimated standard error in the t statistic uses the ______ to estimate the ______ when the population variance is unknown.

An estimated Cohen's d is interpreted in terms of the number of standard deviations that an effect shifted in some population.

Which measure of effect size is most commonly reported with a t test?

A researcher reports that stress levels among nurses are higher compared to stress levels in the general population,t(20) = 2.086,p = .05 (d = .12) .Was this a one-tailed or a two-tailed test?

Cohen's d is a measure of proportion of variance.

A researcher reports that the mean difference in the body weight of rats following a pharmacological versus control treatment is 14 g,with a pooled sample variance equal to 256.What is the effect size for this test using estimated Cohen's d?

Measures of proportion of variance are computed the same for all t tests.

The p value is reported with the test statistic of a one-sample and a two-independent-sample t test using APA format.

When testing a hypothesis with one or two groups selected from a population with an unknown variance,a t test is appropriate.

η\etaη 2 is computed ______ for the one-sample and the two-independent-sample t tests.

State the critical value(s) for a t test using a .05 level of significance in the lower tail only: t(24) .

Normality,random sampling,and independence are all assumptions for the one-sample t test.

State the critical value(s) for the following two-tailed t test at a .05 level of significance: t( ∞\infty∞ ) .

A researcher reports a significant effect with t(14) = 3.24.Compute $\eta$ ² for this result.

A researcher reports a significant mean difference in a given population.If she computes both $\eta$ ² and $\omega$ ² to measure the effect size,then which estimate will be most conservative?

The estimated standard error in the t statistic uses the to estimate the when the population variance is unknown.

$\eta$ ² is computed ______ for the one-sample and the two-independent-sample t tests.

State the critical value(s) for the following two-tailed t test at a .05 level of significance: t( $\infty$ ) .