Question 1

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

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

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

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 the above 
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 the above

Question 5

The average response time to a bank robbery is about 9 minutes.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)minutes.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 6

Is a one-sample t test reported differently for one-tailed and two-tailed tests?

Accepted Answer

A) No,the same values are reported. 
B) It depends on whether the results were significant. 
C) Yes,only significant results for a two-tailed test are reported. 
D) It can be reported differently when the effect size is large. 
A) No,the same values are reported. 
B) It depends on whether the results were significant. 
C) Yes,only significant results for a two-tailed test are reported. 
D) It can be reported differently when the effect size is large.

Question 7

A t statistic estimates the standard error by using the sample variance to approximate the population variance.

Accepted Answer

A) True 
 B)False

Question 8

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

Accepted Answer

A) True 
 B)False

Question 9

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 10

A researcher reports that the mean time it takes to complete an experimental task is 1.4±8.0 (M±SD)seconds.If the null hypothesis was that the mean equals 1.0,then what is the effect size for this test using estimated Cohen's d?

Accepted Answer

A) d = 0.05;small effect size 
B) d = 0.50;medium effect size 
C) d = 1.05;large effect size 
D) There is not enough information to answer this question. 
A) d = 0.05;small effect size 
B) d = 0.50;medium effect size 
C) d = 1.05;large effect size 
D) There is not enough information to answer this question.

Question 11

A researcher reports that the effectiveness of a new marketing campaign significantly increased sales compared with the previous campaign strategy,t(49)= 2.562,p < .05.Use eta-squared to interpret the effect size for this result.

Accepted Answer

A) 12% of the variability in marketing effectiveness can be accounted for by the new marketing strategy. 
B) 12% of the standard error can be accounted for by the effectiveness of the marketing strategy. 
C) Marketing effectiveness shifted 0.12 standard deviations above the mean in the population. 
D) both A and B are correct 
A) 12% of the variability in marketing effectiveness can be accounted for by the new marketing strategy. 
B) 12% of the standard error can be accounted for by the effectiveness of the marketing strategy. 
C) Marketing effectiveness shifted 0.12 standard deviations above the mean in the population. 
D) both A and B are correct

Question 12

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

Accepted Answer

A) eta-squared 
B) omega-squared 
C) t statistic 
D) Cohen's d 
A) eta-squared 
B) omega-squared 
C) t statistic 
D) Cohen's d

Question 13

Normality is the assumption that data in the population are normally distributed.

Accepted Answer

A) True 
 B)False

Question 14

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 15

A researcher reports that the mean difference in the body weight of rats following a pharmacological versus control treatment is 14 grams,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. 
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 16

The mean crying time of infants during naptime at a local preschool is 12 minutes.The school implements a new naptime routine in a sample of 25 infants and records an average crying time of 8±4.6 (M±SD)minutes.Test whether this new naptime routine reduced crying time at a .05 level of significance.

Accepted Answer

A) The new naptime routine significantly reduced crying time,t(24)= -4.35,p  .05. 
D) The new naptime routine significantly reduce crying time,t(24)= 0.92,p < .05. 
A) The new naptime routine significantly reduced crying time,t(24)= -4.35,p  .05. 
D) The new naptime routine significantly reduce crying time,t(24)= 0.92,p < .05.

Question 17

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 18

A researcher records the number of distracters (such as noises)that preschool-aged children ignore while watching a popular Sunday morning cartoon show.Assuming that the population variance is unknown,what type of t test is appropriate for this study?

Accepted Answer

A) one-sample t test 
B) two-independent sample t test 
C) There is not enough information to answer this question. 
A) one-sample t test 
B) two-independent sample t test 
C) There is not enough information to answer this question.

Question 19

A researcher reports the following result for a two-tailed test at a .05 level of significance,t(30)= 2.320,and correctly decides to retain the null hypothesis.

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(   ).

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

Computing a one-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?

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

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

Is a one-sample t test reported differently for one-tailed and two-tailed tests?

A t statistic estimates the standard error by using the sample variance to approximate the population variance.

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

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

A researcher reports that the mean time it takes to complete an experimental task is 1.4±8.0 (M±SD)seconds.If the null hypothesis was that the mean equals 1.0,then what is the effect size for this test using estimated Cohen's d?

A researcher reports that the effectiveness of a new marketing campaign significantly increased sales compared with the previous campaign strategy,t(49)= 2.562,p < .05.Use eta-squared to interpret the effect size for this result.

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

Normality is the assumption that data in the population are normally distributed.

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.

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

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?

A researcher records the number of distracters (such as noises)that preschool-aged children ignore while watching a popular Sunday morning cartoon show.Assuming that the population variance is unknown,what type of t test is appropriate for this study?

A researcher reports the following result for a two-tailed test at a .05 level of significance,t(30)= 2.320,and correctly decides to retain the null hypothesis.

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

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: Related Samples T Test

Estimation and Confidence Intervals

Analysis of Variance: One-Way Between-Subjects Design

Analysis of Variance: One-Way Within-Subjects Repeated Measures Design

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 one-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?

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

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

Is a one-sample t test reported differently for one-tailed and two-tailed tests?

A t statistic estimates the standard error by using the sample variance to approximate the population variance.

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

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

A researcher reports that the mean time it takes to complete an experimental task is 1.4±8.0 (M±SD)seconds.If the null hypothesis was that the mean equals 1.0,then what is the effect size for this test using estimated Cohen's d?

A researcher reports that the effectiveness of a new marketing campaign significantly increased sales compared with the previous campaign strategy,t(49)= 2.562,p < .05.Use eta-squared to interpret the effect size for this result.

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

Normality is the assumption that data in the population are normally distributed.

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.

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

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?

A researcher records the number of distracters (such as noises)that preschool-aged children ignore while watching a popular Sunday morning cartoon show.Assuming that the population variance is unknown,what type of t test is appropriate for this study?

A researcher reports the following result for a two-tailed test at a .05 level of significance,t(30)= 2.320,and correctly decides to retain the null hypothesis.

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

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: Related Samples T Test

Estimation and Confidence Intervals

Analysis of Variance: One-Way Between-Subjects Design

Analysis of Variance: One-Way Within-Subjects Repeated Measures Design

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