Question 1

Compared to a z-score,a hypothesis test with a t statistic requires less information from the population.

Accepted Answer

A) True 
 B)False

Question 2

Which of the following would have no effect on the width of a confidence interval?

Accepted Answer

A) Increase the sample mean 
B) Increase the size of the sample 
C) Increase the percentage of confidence 
D) Increase the sample variance 
A) Increase the sample mean 
B) Increase the size of the sample 
C) Increase the percentage of confidence 
D) Increase the sample variance

Question 3

Why are t statistics more variable than z-scores?

Accepted Answer

A) The extra variability is caused by variations in the sample mean. 
B) The extra variability is caused by variations in the sample variance. 
C) The extra variability is caused by variations in the df value. 
D) None of the other options explains the extra variability for t statistics. 
A) The extra variability is caused by variations in the sample mean. 
B) The extra variability is caused by variations in the sample variance. 
C) The extra variability is caused by variations in the df value. 
D) None of the other options explains the extra variability for t statistics.

Question 4

A sample with a mean of M = 40 and a variance of s2 = 20 has an estimated standard error of 1 point.How many scores are in the sample?

Accepted Answer

A) 4 
B) 5 
C) 20 
D) 21 
A) 4 
B) 5 
C) 20 
D) 21

Question 5

Under what circumstances can a very small treatment effect be statistically significant?

Accepted Answer

A) If the sample size big and the sample variance is small 
B) If the sample size and the sample variance are both big 
C) If the sample size is small and the sample variance is big 
D) If the sample size and the sample variance are both small 
A) If the sample size big and the sample variance is small 
B) If the sample size and the sample variance are both big 
C) If the sample size is small and the sample variance is big 
D) If the sample size and the sample variance are both small

Question 6

If a sample of n = 16 scores is being used to make an 80% confidence interval estimate of the population mean,μ,what value(s)of t should be used?

Accepted Answer

A) t = 0 
B) t = ±2.131 
C) t = ±1.753 
D) t = ±1.341 
A) t = 0 
B) t = ±2.131 
C) t = ±1.753 
D) t = ±1.341

Question 7

If a hypothesis test using a sample of n = 16 scores produces a t statistic of t = 2.15,then the correct decision is to reject the null hypothesis for a two-tailed test with  = .05.

Accepted Answer

A) True 
 B)False

Question 8

A researcher is using a two-tailed hypothesis test with α = .05 to evaluate the effect of a treatment.If the boundaries for the critical region are t = ± 2.080,then how many individuals are in the sample?

Accepted Answer

A) n = 22 
B) n = 21 
C) n = 20 
D) Impossible to determine without more information 
A) n = 22 
B) n = 21 
C) n = 20 
D) Impossible to determine without more information

Question 9

If other factors are held constant,as the sample variance increases,the estimated standard error also increases.

Accepted Answer

A) True 
 B)False

Question 10

If two samples from the same population are the same size and have the same mean,then they will have the same t statistic.

Accepted Answer

A) True 
 B)False

Question 11

A random sample with n = 20 scores has df = 19.

Accepted Answer

A) True 
 B)False

Question 12

A sample of n = 4 scores is selected from a population with an unknown mean.The sample has a mean of M = 40 and a variance of s2 = 16.Which of the following is the correct 90% confidence interval for μ?

Accepted Answer

A) μ = 40 ± 2.353(4) 
B) μ = 40 ± 1.638(4) 
C) μ = 40 ± 2.353(2) 
D) μ = 40 ± 1.638(2) 
A) μ = 40 ± 2.353(4) 
B) μ = 40 ± 1.638(4) 
C) μ = 40 ± 2.353(2) 
D) μ = 40 ± 1.638(2)

Question 13

For a two-tailed test with α = .05 and a sample of n = 16,the boundaries for the critical region are t = ±2.120.

Accepted Answer

A) True 
 B)False

Question 14

If two samples,each with n = 20 scores,are selected from the same population and both have the same mean (M = 53)and the same variance (s2 = 12),then they will also have the same t statistic.

Accepted Answer

A) True 
 B)False

Question 15

Two samples from the same population both have n = 10 scores with M = 45.If the t statistic is computed for each sample,then what is the relationship between the two t values?

Accepted Answer

A) The two t statistics will be identical. 
B) The sample with the larger variance will produce the larger t statistic. 
C) The sample with the smaller variance will produce the larger t statistic. 
D) There is no way to predict the relationship between the two t statistics. 
A) The two t statistics will be identical. 
B) The sample with the larger variance will produce the larger t statistic. 
C) The sample with the smaller variance will produce the larger t statistic. 
D) There is no way to predict the relationship between the two t statistics.

Question 16

A research report states "t(8)= 2.00,p > .05." For this test,r2 = 2/10.

Accepted Answer

A) True 
 B)False

Question 17

The sample mean will always be exactly in the center of a confidence interval that is estimating the value of the population mean.

Accepted Answer

A) True 
 B)False

Question 18

A sample of n = 25 scores produces a t statistic of t = 2.062.If the researcher is using a two-tailed test,which of the following is the correct statistical decision?

Accepted Answer

A) The researcher can reject the null hypothesis with α = .05 but not with α = .01. 
B) The researcher can reject the null hypothesis with either α = .05 or α = .01. 
C) The researcher must fail to reject the null hypothesis with either α = .05 or α = .01. 
D) It is impossible to make a decision about H0 without more information. 
A) The researcher can reject the null hypothesis with α = .05 but not with α = .01. 
B) The researcher can reject the null hypothesis with either α = .05 or α = .01. 
C) The researcher must fail to reject the null hypothesis with either α = .05 or α = .01. 
D) It is impossible to make a decision about H0 without more information.

Question 19

For a one-tailed test evaluating a treatment that is supposed to decrease scores,a researcher obtains t(8)= F1F1F1S1F1F1F101.90.For α = .05,the correct decision is to reject the null hypothesis.

Accepted Answer

A) True 
 B)False

Question 20

How does sample variance influence the estimated standard error and measures of effect size such as r2 and Cohen's d?

Accepted Answer

A) Larger variance increases both the standard error and measures of effect size. 
B) Larger variance increases the standard error but decreases measures of effect size. 
C) Larger variance decreases the standard error but increases measures of effect size. 
D) Larger variance decreases both the standard error and measures of effect size. 
A) Larger variance increases both the standard error and measures of effect size. 
B) Larger variance increases the standard error but decreases measures of effect size. 
C) Larger variance decreases the standard error but increases measures of effect size. 
D) Larger variance decreases both the standard error and measures of effect size.

Compared to a z-score,a hypothesis test with a t statistic requires less information from the population.

Which of the following would have no effect on the width of a confidence interval?

Why are t statistics more variable than z-scores?

A sample with a mean of M = 40 and a variance of s² = 20 has an estimated standard error of 1 point.How many scores are in the sample?

Under what circumstances can a very small treatment effect be statistically significant?

If a sample of n = 16 scores is being used to make an 80% confidence interval estimate of the population mean,μ,what value(s)of t should be used?

If a hypothesis test using a sample of n = 16 scores produces a t statistic of t = 2.15,then the correct decision is to reject the null hypothesis for a two-tailed test with  = .05.

A researcher is using a two-tailed hypothesis test with α = .05 to evaluate the effect of a treatment.If the boundaries for the critical region are t = ± 2.080,then how many individuals are in the sample?

If other factors are held constant,as the sample variance increases,the estimated standard error also increases.

If two samples from the same population are the same size and have the same mean,then they will have the same t statistic.

A random sample with n = 20 scores has df = 19.

A sample of n = 4 scores is selected from a population with an unknown mean.The sample has a mean of M = 40 and a variance of s² = 16.Which of the following is the correct 90% confidence interval for μ?

For a two-tailed test with α = .05 and a sample of n = 16,the boundaries for the critical region are t = ±2.120.

If two samples,each with n = 20 scores,are selected from the same population and both have the same mean (M = 53)and the same variance (s² = 12),then they will also have the same t statistic.

Two samples from the same population both have n = 10 scores with M = 45.If the t statistic is computed for each sample,then what is the relationship between the two t values?

A research report states "t(8)= 2.00,p > .05." For this test,r² = 2/10.

The sample mean will always be exactly in the center of a confidence interval that is estimating the value of the population mean.

A sample of n = 25 scores produces a t statistic of t = 2.062.If the researcher is using a two-tailed test,which of the following is the correct statistical decision?

For a one-tailed test evaluating a treatment that is supposed to decrease scores,a researcher obtains t(8)= 1.90.For α = .05,the correct decision is to reject the null hypothesis.

How does sample variance influence the estimated standard error and measures of effect size such as r² and Cohen's d?

Introduction to Statistics

Frequency Distributions

Measures of Central Tendency

Measures of Variability

Z-Scores

Probability

Probability and Samples:

Introduction to Hypothesis Testing

The T Test for Two Independent Samples

The T Test for Two Related Samples

Introduction to Analysis of Variance

Repeated-Measures and Two-Factor Anova

Correlation and Regression

Chi-Square Tests

Filters

Exam 9: Introduction to the T Statistic

Compared to a z-score,a hypothesis test with a t statistic requires less information from the population.

Which of the following would have no effect on the width of a confidence interval?

Why are t statistics more variable than z-scores?

A sample with a mean of M = 40 and a variance of s2 = 20 has an estimated standard error of 1 point.How many scores are in the sample?

Under what circumstances can a very small treatment effect be statistically significant?

If a sample of n = 16 scores is being used to make an 80% confidence interval estimate of the population mean,μ,what value(s)of t should be used?

If a hypothesis test using a sample of n = 16 scores produces a t statistic of t = 2.15,then the correct decision is to reject the null hypothesis for a two-tailed test with  = .05.

A researcher is using a two-tailed hypothesis test with α = .05 to evaluate the effect of a treatment.If the boundaries for the critical region are t = ± 2.080,then how many individuals are in the sample?

If other factors are held constant,as the sample variance increases,the estimated standard error also increases.

If two samples from the same population are the same size and have the same mean,then they will have the same t statistic.

A random sample with n = 20 scores has df = 19.

A sample of n = 4 scores is selected from a population with an unknown mean.The sample has a mean of M = 40 and a variance of s2 = 16.Which of the following is the correct 90% confidence interval for μ?

For a two-tailed test with α = .05 and a sample of n = 16,the boundaries for the critical region are t = ±2.120.

If two samples,each with n = 20 scores,are selected from the same population and both have the same mean (M = 53)and the same variance (s2 = 12),then they will also have the same t statistic.

Two samples from the same population both have n = 10 scores with M = 45.If the t statistic is computed for each sample,then what is the relationship between the two t values?

A research report states "t(8)= 2.00,p > .05." For this test,r2 = 2/10.

The sample mean will always be exactly in the center of a confidence interval that is estimating the value of the population mean.

A sample of n = 25 scores produces a t statistic of t = 2.062.If the researcher is using a two-tailed test,which of the following is the correct statistical decision?

For a one-tailed test evaluating a treatment that is supposed to decrease scores,a researcher obtains t(8)= 1.90.For α = .05,the correct decision is to reject the null hypothesis.

How does sample variance influence the estimated standard error and measures of effect size such as r2 and Cohen's d?

Introduction to Statistics

Frequency Distributions

Measures of Central Tendency

Measures of Variability

Z-Scores

Probability

Probability and Samples:

Introduction to Hypothesis Testing

The T Test for Two Independent Samples

The T Test for Two Related Samples

Introduction to Analysis of Variance

Repeated-Measures and Two-Factor Anova

Correlation and Regression

Chi-Square Tests

Filters

A sample with a mean of M = 40 and a variance of s² = 20 has an estimated standard error of 1 point.How many scores are in the sample?

A sample of n = 4 scores is selected from a population with an unknown mean.The sample has a mean of M = 40 and a variance of s² = 16.Which of the following is the correct 90% confidence interval for μ?

If two samples,each with n = 20 scores,are selected from the same population and both have the same mean (M = 53)and the same variance (s² = 12),then they will also have the same t statistic.

A research report states "t(8)= 2.00,p > .05." For this test,r² = 2/10.

How does sample variance influence the estimated standard error and measures of effect size such as r² and Cohen's d?