Question 1

Computing a two-independent-sample t test is appropriate when

Accepted Answer

A)  different participants are assigned to each of two groups. 
B)  the population variance is unknown. 
C)  participants are observed one time in a given group. 
D)  all of these. 
A)  different participants are assigned to each of two groups. 
B)  the population variance is unknown. 
C)  participants are observed one time in a given group. 
D)  all of these.

Question 2

Two researchers (A and B)compute a two-independent-sample t test.For both tests,the mean difference between the two groups is 10,but the standard error is smaller for Researcher A.Which test is more likely to result in a decision to reject the null hypothesis?

Accepted Answer

A)  Researcher A. 
B)  Researcher B. 
C)  The likelihood is the same for both researchers. 
D)  There is not enough information to answer this question. 
A)  Researcher A. 
B)  Researcher B. 
C)  The likelihood is the same for both researchers. 
D)  There is not enough information to answer this question.

Question 3

Computing a one-sample t test is appropriate when

Accepted Answer

A)  participants are assigned to only one group. 
B)  the population variance is unknown. 
C)  participants are observed one time. 
D)  all of these. 
A)  participants are assigned to only one group. 
B)  the population variance is unknown. 
C)  participants are observed one time. 
D)  all of these.

Question 4

A one-sample t test will be t = 0 when the standard error is equal to 0.

Accepted Answer

A) True 
 B)False

Question 5

A researcher reports the following result for a two-tailed test at a .05 level of significance,t(30)= 2.020,and correctly decides to retain the null hypothesis.

Accepted Answer

A) True 
 B)False

Question 6

The average response time to a bank robbery is about 9 min.A local community wants to improve on this time,so they implement advanced training seminars.They find that the new response time for a sample of 36 police officers is 8 ± 4.2 (M ± SD)min.Test whether this advanced training seminar reduced response time at a .05 level of significance.

Accepted Answer

A)  This advanced training seminar significantly reduced response time, t(35) = 11.43, p  .05. 
D)  There is not enough information to answer this question. 
A)  This advanced training seminar significantly reduced response time, t(35) = 11.43, p  .05. 
D)  There is not enough information to answer this question.

Question 7

As the degrees of freedom for a t test increase,the critical values for that test also increase.

Accepted Answer

A) True 
 B)False

Question 8

Two researchers (A and B)compute a two-independent-sample t test.For both tests,the standard error is the same,but the mean difference between the groups is larger for Researcher A.Which test is more likely to result in a decision to reject the null hypothesis?

Accepted Answer

A)  Researcher A. 
B)  Researcher B. 
C)  The likelihood is the same for both researchers. 
D)  There is not enough information to answer this question. 
A)  Researcher A. 
B)  Researcher B. 
C)  The likelihood is the same for both researchers. 
D)  There is not enough information to answer this question.

Question 9

To compute a two-independent-sample t test,a researcher has to know many values.Which of the following is NOT a value that the researcher must know to compute this test?

Accepted Answer

A)  the pooled sample variance 
B)  the pooled population variance 
C)  the sample size for both samples 
D)  the sample mean for both samples 
A)  the pooled sample variance 
B)  the pooled population variance 
C)  the sample size for both samples 
D)  the sample mean for both samples

Question 10

The t distribution is similar to the z distribution,except

Accepted Answer

A)  it is associated with greater variability. 
B)  it is characterized by "thicker" tails compared with the z distribution. 
C)  it is associated with scores being more likely in the tails of the distribution. 
D)  all of these. 
A)  it is associated with greater variability. 
B)  it is characterized by "thicker" tails compared with the z distribution. 
C)  it is associated with scores being more likely in the tails of the distribution. 
D)  all of these.

Question 11

A researcher reports the following result for a lower-tail critical test at a .05 level of significance,t(40)= 1.512,and accurately concludes to reject the null hypothesis.

Accepted Answer

A) True 
 B)False

Question 12

A researcher has participants rate the likability of a sexually promiscuous person described in a vignette as being male (n = 20)or female (n = 12).The mean likability ratings in each group were 4.0.If the null hypothesis is that there is no difference in likability ratings,then do likability ratings differ at a .05 level of significance?

Accepted Answer

A)  Yes, this result is significant, p < .05. 
B)  No, this result is not significant, t(30) = 0. 
C)  No, this result is not significant, t(30) = 1.00. 
D)  There is not enough information to answer this question because the variance in each sample is not given. 
A)  Yes, this result is significant, p < .05. 
B)  No, this result is not significant, t(30) = 0. 
C)  No, this result is not significant, t(30) = 1.00. 
D)  There is not enough information to answer this question because the variance in each sample is not given.

Question 13

A two-independent-sample t test is used when the same participants are observed two times.

Accepted Answer

A) True 
 B)False

Question 14

A researcher reports that mean ratings of liking for some food are 0.8 ± 2.4 (M ± SD).If the null hypothesis was that the mean equals 0,then what is the effect size for this test using estimated Cohen's d?

Accepted Answer

A)  d = 0.33; small effect size 
B)  d = 0.33; medium effect size 
C)  d = 3.00; large effect size 
D)  There is not enough information to answer this question. 
A)  d = 0.33; small effect size 
B)  d = 0.33; medium effect size 
C)  d = 3.00; large effect size 
D)  There is not enough information to answer this question.

Question 15

A researcher reports that the mean difference in response time to an auditory versus a visual cue is 0.83 s,with a pooled sample variance equal to 2.45.What is the effect size for this test using estimated Cohen's d?

Accepted Answer

A)  d = 0.53; medium effect size 
B)  d = 0.53; large effect size 
C)  d = 0.34; small effect size 
D)  d = 0.34; medium effect size 
A)  d = 0.53; medium effect size 
B)  d = 0.53; large effect size 
C)  d = 0.34; small effect size 
D)  d = 0.34; medium effect size

Question 16

A researcher reports a significant effect in some population.If she computes both an $\eta$2 and an $\omega$2 effect size estimate,then which estimate will be the largest?

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

Question 17

A two-independent-sample t test is computed when mean differences are compared between two or more groups sampled from a population with an unknown variance.

Accepted Answer

A) True 
 B)False

Question 18

A researcher reports that the mean difference between two groups is 20.12 and the estimated standard error for the difference is 2.83.Hence,the conclusion must be to reject the null hypothesis for a two-tailed test at a .05 level of significance.

Accepted Answer

A) True 
 B)False

Question 19

If d = 0.28,then we conclude that mean scores in some population have shifted 0.28 standard deviations below the mean.

Accepted Answer

A) True 
 B)False

Question 20

A one-sample t test will be undefined (denominator = 0)when the same score is recorded for all participants in a study.

Accepted Answer

A) True 
 B)False

Computing a two-independent-sample t test is appropriate when

Two researchers (A and B)compute a two-independent-sample t test.For both tests,the mean difference between the two groups is 10,but the standard error is smaller for Researcher A.Which test is more likely to result in a decision to reject the null hypothesis?

Computing a one-sample t test is appropriate when

A one-sample t test will be t = 0 when the standard error is equal to 0.

A researcher reports the following result for a two-tailed test at a .05 level of significance,t(30)= 2.020,and correctly decides to retain the null hypothesis.

As the degrees of freedom for a t test increase,the critical values for that test also increase.

Two researchers (A and B)compute a two-independent-sample t test.For both tests,the standard error is the same,but the mean difference between the groups is larger for Researcher A.Which test is more likely to result in a decision to reject the null hypothesis?

To compute a two-independent-sample t test,a researcher has to know many values.Which of the following is NOT a value that the researcher must know to compute this test?

The t distribution is similar to the z distribution,except

A researcher reports the following result for a lower-tail critical test at a .05 level of significance,t(40)= 1.512,and accurately concludes to reject the null hypothesis.

A two-independent-sample t test is used when the same participants are observed two times.

A researcher reports that mean ratings of liking for some food are 0.8 ± 2.4 (M ± SD).If the null hypothesis was that the mean equals 0,then what is the effect size for this test using estimated Cohen's d?

A researcher reports that the mean difference in response time to an auditory versus a visual cue is 0.83 s,with a pooled sample variance equal to 2.45.What is the effect size for this test using estimated Cohen's d?

A researcher reports a significant effect in some population.If she computes both an $\eta$ ² and an $\omega$ ² effect size estimate,then which estimate will be the largest?

A two-independent-sample t test is computed when mean differences are compared between two or more groups sampled from a population with an unknown variance.

A researcher reports that the mean difference between two groups is 20.12 and the estimated standard error for the difference is 2.83.Hence,the conclusion must be to reject the null hypothesis for a two-tailed test at a .05 level of significance.

If d = 0.28,then we conclude that mean scores in some population have shifted 0.28 standard deviations below the mean.

A one-sample t test will be undefined (denominator = 0)when the same score is recorded for all participants in a study.

Introduction to Statistics

Summarizing Data: Frequency Distributions in Tables and Graphs

Summarizing Data: Central Tendency

Summarizing Data: Variability

Probability

Probability, normal Distributions, and Z Scores

Probability and Sampling Distributions

Hypothesis Testing: Significance,effect Size,and Power

Testing Means: Truehe Related-Samples T Test

Estimation and Confidence Intervals

Analysis of Variance: One-Way Between-Subjects Design

Analysis of Variance: One-Way Within-Subjects Repeated-Measuresdesign

Analysis of Variance: Two-Way Between-Subjects Factorial Design

Correlation

Linear Regression and Multiple Regression

Nonparametric Tests: Chi-Square Tests

Nonparametric Tests: Tests for Ordinal Data

Filters

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

Computing a two-independent-sample t test is appropriate when

Two researchers (A and B)compute a two-independent-sample t test.For both tests,the mean difference between the two groups is 10,but the standard error is smaller for Researcher A.Which test is more likely to result in a decision to reject the null hypothesis?

Computing a one-sample t test is appropriate when

A one-sample t test will be t = 0 when the standard error is equal to 0.

A researcher reports the following result for a two-tailed test at a .05 level of significance,t(30)= 2.020,and correctly decides to retain the null hypothesis.

As the degrees of freedom for a t test increase,the critical values for that test also increase.

Two researchers (A and B)compute a two-independent-sample t test.For both tests,the standard error is the same,but the mean difference between the groups is larger for Researcher A.Which test is more likely to result in a decision to reject the null hypothesis?

To compute a two-independent-sample t test,a researcher has to know many values.Which of the following is NOT a value that the researcher must know to compute this test?

The t distribution is similar to the z distribution,except

A researcher reports the following result for a lower-tail critical test at a .05 level of significance,t(40)= 1.512,and accurately concludes to reject the null hypothesis.

A two-independent-sample t test is used when the same participants are observed two times.

A researcher reports that mean ratings of liking for some food are 0.8 ± 2.4 (M ± SD).If the null hypothesis was that the mean equals 0,then what is the effect size for this test using estimated Cohen's d?

A researcher reports that the mean difference in response time to an auditory versus a visual cue is 0.83 s,with a pooled sample variance equal to 2.45.What is the effect size for this test using estimated Cohen's d?

A researcher reports a significant effect in some population.If she computes both an η\etaη 2 and an ω\omegaω 2 effect size estimate,then which estimate will be the largest?

A two-independent-sample t test is computed when mean differences are compared between two or more groups sampled from a population with an unknown variance.

A researcher reports that the mean difference between two groups is 20.12 and the estimated standard error for the difference is 2.83.Hence,the conclusion must be to reject the null hypothesis for a two-tailed test at a .05 level of significance.

If d = 0.28,then we conclude that mean scores in some population have shifted 0.28 standard deviations below the mean.

A one-sample t test will be undefined (denominator = 0)when the same score is recorded for all participants in a study.

Introduction to Statistics

Summarizing Data: Frequency Distributions in Tables and Graphs

Summarizing Data: Central Tendency

Summarizing Data: Variability

Probability

Probability, normal Distributions, and Z Scores

Probability and Sampling Distributions

Hypothesis Testing: Significance,effect Size,and Power

Testing Means: Truehe Related-Samples T Test

Estimation and Confidence Intervals

Analysis of Variance: One-Way Between-Subjects Design

Analysis of Variance: One-Way Within-Subjects Repeated-Measuresdesign

Analysis of Variance: Two-Way Between-Subjects Factorial Design

Correlation

Linear Regression and Multiple Regression

Nonparametric Tests: Chi-Square Tests

Nonparametric Tests: Tests for Ordinal Data

Filters

A researcher reports a significant effect in some population.If she computes both an $\eta$ ² and an $\omega$ ² effect size estimate,then which estimate will be the largest?