Question 1

If a researcher is using a t statistic to test a null hypothesis about a population,what information is needed from the population to calculate the t statistic?

Accepted Answer

A) You must know the population mean. 
B) You must know the population variance or standard deviation. 
C) You must know the population mean and the variance or standard deviation. 
D) The t statistic does not require any information about the population. 
A) You must know the population mean. 
B) You must know the population variance or standard deviation. 
C) You must know the population mean and the variance or standard deviation. 
D) The t statistic does not require any information about the population.

Question 2

A sample is selected from a population with ? = 70,and a treatment is administered to the sample.After treatment,the sample mean is M = 74,and Cohen's d is d = 1.00.What is the value of the sample variance?

Accepted Answer

A) s2 = 2 
B) s2 = 4 
C) s2 = 16 
D) It is impossible to determine the sample variance without more information. 
A) s2 = 2 
B) s2 = 4 
C) s2 = 16 
D) It is impossible to determine the sample variance without more information.

Question 3

For a two-tailed hypothesis test with α = .05 and a sample of n = 25 scores,the boundaries for the critical region are t = ±2.060.

Accepted Answer

A) True 
 B)False

Question 4

Which of the following is the correct way to report the results of a hypothesis test and a measure of effect size using a t statistic?

Accepted Answer

A) t(19) = 2.30, r² = 0.42, p < .05 
B) t(19) = 2.30, p < .05, r² = 0.42, 
C) r² = 0.42, t(19) = 2.30 , p < .05 
D) t = 2.30, df = 19, p < .05, r² = 0.42 
A) t(19) = 2.30, r² = 0.42, p < .05 
B) t(19) = 2.30, p < .05, r² = 0.42, 
C) r² = 0.42, t(19) = 2.30 , p < .05 
D) t = 2.30, df = 19, p < .05, r² = 0.42

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 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 α = .05.

Accepted Answer

A) True 
 B)False

Question 7

A sample of n = 16 individuals is selected from a population with µ = 30.After a treatment is administered to the individuals,the sample mean is found to be M = 33.
a.Assume the sample variance is s² = 16, then conduct a hypothesis test to evaluate the
significance of the treatment effect and calculate r² to measure the size of the
treatment effect.Use a two-tailed test with α = .05.
b.Assume the sample variance is s² = 64, then conduct a hypothesis test to evaluate the
significance of the treatment effect and calculate r² to measure the size of the
treatment effect.Use a two-tailed test with α = .05.
c.Describe how increasing variance affects the likelihood of rejecting the
null hypothesis and the measure of effect size.

Accepted Answer

a.The standard error is 1 and t = 3.00.W

Question 8

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.

Accepted Answer

A) True 
 B)False

Question 9

Which of the following samples will have the smallest value for the estimated standard error?

Accepted Answer

A) n = 4 with s2 = 16 
B) n = 4 with s2 = 64 
C) n = 16 with s2 = 16 
D) n = 16 with s2 = 64 
A) n = 4 with s2 = 16 
B) n = 4 with s2 = 64 
C) n = 16 with s2 = 16 
D) n = 16 with s2 = 64

Question 10

A hypothesis test produces a t statistic of t = 2.20.If the researcher is using a two-tailed test with α = .05,how large does the sample have to be in order to reject the null hypothesis?

Accepted Answer

A) At least n = 11 
B) At least n = 12 
C) At least n = 13 
D) At least n = 14 
A) At least n = 11 
B) At least n = 12 
C) At least n = 13 
D) At least n = 14

Question 11

A sample is selected from a population with µ = 50.After a treatment is administered to the individuals in the sample,the mean is found to be M = 55 and the variance is s² = 64.
a.For a sample of n = 4 scores, conduct a hypothesis test to evaluate the
significance of the treatment effect and calculate Cohen's d to measure the size of the
treatment effect.Use a two-tailed test with α = .05.
b.For a sample of n = 16 scores, conduct a hypothesis test to evaluate the
significance of the treatment effect and calculate Cohen's d to measure the size of the
treatment effect.Use a two-tailed test with α = .05.
c.Describe how increasing the size of the sample affects the likelihood of rejecting the
null hypothesis and the measure of effect size.

Accepted Answer

a.The standard error is 4 and t = 1.25.W

Question 12

A sample of n = 4 scores has SS = 60.What is the variance for this sample?

Accepted Answer

A) 30 
B) 20 
C) 16 
D) 15 
A) 30 
B) 20 
C) 16 
D) 15

Question 13

If other factors are held constant,how does sample variance influence the likelihood of rejecting the null hypothesis and measures of effect size such as r² and Cohen's d?

Accepted Answer

A) Larger sample variance increases both the likelihood and measures of effect size. 
B) Larger sample variance increases the likelihood but has little influence on measures of effect size. 
C) Larger sample variance decreases the likelihood but has little influence on measures of effect size. 
D) Larger sample variance decreases both the likelihood and measures of effect size. 
A) Larger sample variance increases both the likelihood and measures of effect size. 
B) Larger sample variance increases the likelihood but has little influence on measures of effect size. 
C) Larger sample variance decreases the likelihood but has little influence on measures of effect size. 
D) Larger sample variance decreases both the likelihood and measures of effect size.

Question 14

As sample size increases,the critical region boundaries for a two-tailed t-test with α = .05 will move closer to zero.

Accepted Answer

A) True 
 B)False

Question 15

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 16

The results of a hypothesis test are reported as follows: t(15)= 2.70,p < .05.Based on this report,how many individuals were in the sample?

Accepted Answer

A) 14 
B) 15 
C) 16 
D) Cannot be determined from the information provided 
A) 14 
B) 15 
C) 16 
D) Cannot be determined from the information provided

Question 17

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

Accepted Answer

A) True 
 B)False

Question 18

Although you can compute a z-score for a single score (a sample of n = 1),it is impossible to compute a t statistic for a sample that has only one score.Explain why.

Accepted Answer

Before you can find a t statis

Question 19

A sample of n = 16 scores has a mean of M = 58 with SS = 960.Use the sample to construct the 90% confidence interval for µ.

Accepted Answer

The sample variance is s² = 64

Question 20

Two samples from the same population both have M = 84 and s2 = 20,but one sample has n = 10 and the other has n = 20 scores.Both samples are used to evaluate a hypothesis stating that ? = 80 and to compute Cohen's d.How will the outcomes for the two samples compare?

Accepted Answer

A) The larger sample is more likely to reject the hypothesis and will produce a larger value for Cohen's d. 
B) The larger sample is more likely to reject the hypothesis, but the two samples will have the same value for Cohen's d. 
C) The larger sample is less likely to reject the hypothesis and will produce a larger value for Cohen's d. 
D) The larger sample is less likely to reject the hypothesis, but the two samples will have the same value for Cohen's d. 
A) The larger sample is more likely to reject the hypothesis and will produce a larger value for Cohen's d. 
B) The larger sample is more likely to reject the hypothesis, but the two samples will have the same value for Cohen's d. 
C) The larger sample is less likely to reject the hypothesis and will produce a larger value for Cohen's d. 
D) The larger sample is less likely to reject the hypothesis, but the two samples will have the same value for Cohen's d.

If a researcher is using a t statistic to test a null hypothesis about a population,what information is needed from the population to calculate the t statistic?

A sample is selected from a population with ? = 70,and a treatment is administered to the sample.After treatment,the sample mean is M = 74,and Cohen's d is d = 1.00.What is the value of the sample variance?

For a two-tailed hypothesis test with α = .05 and a sample of n = 25 scores,the boundaries for the critical region are t = ±2.060.

Which of the following is the correct way to report the results of a hypothesis test and a measure of effect size using a t statistic?

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

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 α = .05.

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.

Which of the following samples will have the smallest value for the estimated standard error?

A hypothesis test produces a t statistic of t = 2.20.If the researcher is using a two-tailed test with α = .05,how large does the sample have to be in order to reject the null hypothesis?

A sample of n = 4 scores has SS = 60.What is the variance for this sample?

If other factors are held constant,how does sample variance influence the likelihood of rejecting the null hypothesis and measures of effect size such as r² and Cohen's d?

As sample size increases,the critical region boundaries for a two-tailed t-test with α = .05 will move closer to zero.

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

The results of a hypothesis test are reported as follows: t(15)= 2.70,p < .05.Based on this report,how many individuals were in the sample?

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

Although you can compute a z-score for a single score (a sample of n = 1),it is impossible to compute a t statistic for a sample that has only one score.Explain why.

A sample of n = 16 scores has a mean of M = 58 with SS = 960.Use the sample to construct the 90% confidence interval for µ.

Two samples from the same population both have M = 84 and s² = 20,but one sample has n = 10 and the other has n = 20 scores.Both samples are used to evaluate a hypothesis stating that ? = 80 and to compute Cohen's d.How will the outcomes for the two samples compare?

Introduction to Statistics.

Frequency Distributions.

Central Tendency.

Variability.

z-Scores: Location of Scores and Standardized Distributions.

Probability.

Probability and Samples: The Distribution of Sample Means.

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 Analysis of Variance

Correlation and Regression.

The Chi-Square Statistic: Tests for Goodness of Fit and Independence

Filters

Exam 9: Introduction to the t Statistic

If a researcher is using a t statistic to test a null hypothesis about a population,what information is needed from the population to calculate the t statistic?

A sample is selected from a population with ? = 70,and a treatment is administered to the sample.After treatment,the sample mean is M = 74,and Cohen's d is d = 1.00.What is the value of the sample variance?

For a two-tailed hypothesis test with α = .05 and a sample of n = 25 scores,the boundaries for the critical region are t = ±2.060.

Which of the following is the correct way to report the results of a hypothesis test and a measure of effect size using a t statistic?

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

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 α = .05.

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.

Which of the following samples will have the smallest value for the estimated standard error?

A hypothesis test produces a t statistic of t = 2.20.If the researcher is using a two-tailed test with α = .05,how large does the sample have to be in order to reject the null hypothesis?

A sample of n = 4 scores has SS = 60.What is the variance for this sample?

If other factors are held constant,how does sample variance influence the likelihood of rejecting the null hypothesis and measures of effect size such as r² and Cohen's d?

As sample size increases,the critical region boundaries for a two-tailed t-test with α = .05 will move closer to zero.

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

The results of a hypothesis test are reported as follows: t(15)= 2.70,p < .05.Based on this report,how many individuals were in the sample?

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

Although you can compute a z-score for a single score (a sample of n = 1),it is impossible to compute a t statistic for a sample that has only one score.Explain why.

A sample of n = 16 scores has a mean of M = 58 with SS = 960.Use the sample to construct the 90% confidence interval for µ.

Two samples from the same population both have M = 84 and s2 = 20,but one sample has n = 10 and the other has n = 20 scores.Both samples are used to evaluate a hypothesis stating that ? = 80 and to compute Cohen's d.How will the outcomes for the two samples compare?

Introduction to Statistics.

Frequency Distributions.

Central Tendency.

Variability.

z-Scores: Location of Scores and Standardized Distributions.

Probability.

Probability and Samples: The Distribution of Sample Means.

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 Analysis of Variance

Correlation and Regression.

The Chi-Square Statistic: Tests for Goodness of Fit and Independence

Filters

Two samples from the same population both have M = 84 and s² = 20,but one sample has n = 10 and the other has n = 20 scores.Both samples are used to evaluate a hypothesis stating that ? = 80 and to compute Cohen's d.How will the outcomes for the two samples compare?