Question 1

A sample of n = 16 scores has a mean of M = 65 and an estimated standard error of 2 points.What is the sample variance?

Accepted Answer

A) s2 = 64 
B) s2 = 36 
C) s2 = 16 
D) s2 = 4 
A) s2 = 64 
B) s2 = 36 
C) s2 = 16 
D) s2 = 4

Question 2

If the 90% confidence interval for µ is from 40 to 50,then the sample mean is M = 45.

Accepted Answer

A) True 
 B)False

Question 3

A hypothesis test with a sample of n = 25 participants produces a t statistic of t = +2.53.Assuming a one-tailed test with the critical region in the right-hand tail,what is the correct 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 4

If other factors are held constant,what is the effect of increasing the sample size?

Accepted Answer

A) It will increase the estimated standard error and increase the likelihood of rejecting H0. 
B) It will increase the estimated standard error and decrease the likelihood of rejecting H0. 
C) It will decrease the estimated standard error and increase the likelihood of rejecting H0. 
D) It will decrease the estimated standard error and decrease the likelihood of rejecting H0. 
A) It will increase the estimated standard error and increase the likelihood of rejecting H0. 
B) It will increase the estimated standard error and decrease the likelihood of rejecting H0. 
C) It will decrease the estimated standard error and increase the likelihood of rejecting H0. 
D) It will decrease the estimated standard error and decrease the likelihood of rejecting H0.

Question 5

What value is estimated with a confidence interval using the t statistic?

Accepted Answer

A) The value for an unknown sample mean 
B) The value for an unknown population mean 
C) The difference between two population means 
D) The difference between two sample means 
A) The value for an unknown sample mean 
B) The value for an unknown population mean 
C) The difference between two population means 
D) The difference between two sample means

Question 6

A researcher selects a sample from a population with a mean of µ = 40 and administers a treatment to the individuals in the sample.If the treatment is expected to decrease scores,which of the following is the correct statement of the null hypothesis for a one-tailed test?

Accepted Answer

A) µ > 20 B) µ 40 D) µ < 80 A) µ > 20 B) µ 40 D) µ < 80

Question 7

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 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

Two samples are selected from a population,and a treatment is administered to the samples.If both samples have the same mean and the same variance,you are more likely to find a significant treatment effect with a sample of n = 100 than with a sample of n = 4.

Accepted Answer

A) True 
 B)False

Question 10

A sample is selected from a population with μ = 46,and a treatment is administered to the sample.After treatment,the sample mean is M = 48 with a sample variance of s² = 16.Based on this information,what is the value of Cohen's d?

Accepted Answer

A) d = 0.125 
B) d = 0.25 
C) d = 0.50 
D) Cohen's d cannot be computed without knowing the sample size. 
A) d = 0.125 
B) d = 0.25 
C) d = 0.50 
D) Cohen's d cannot be computed without knowing the sample size.

Question 11

If other factors are held constant,what is the effect of increasing the sample variance?

Accepted Answer

A) It will increase the estimated standard error and increase the likelihood of rejecting H0. 
B) It will increase the estimated standard error and decrease the likelihood of rejecting H0. 
C) It will decrease the estimated standard error and increase the likelihood of rejecting H0. 
D) It will decrease the estimated standard error and decrease the likelihood of rejecting H0. 
A) It will increase the estimated standard error and increase the likelihood of rejecting H0. 
B) It will increase the estimated standard error and decrease the likelihood of rejecting H0. 
C) It will decrease the estimated standard error and increase the likelihood of rejecting H0. 
D) It will decrease the estimated standard error and decrease the likelihood of rejecting H0.

Question 12

What is the sample variance and the estimated standard error for a sample of n = 9 scores with SS = 72?

Accepted Answer

A) s2 = 9 and sM = 3 
B) s2 = 9 and sM = 1 
C) s2 = 3 and sM = 3 
D) s2 = 3 and sM = 1 
A) s2 = 9 and sM = 3 
B) s2 = 9 and sM = 1 
C) s2 = 3 and sM = 3 
D) s2 = 3 and sM = 1

Question 13

A researcher conducts a hypothesis test using a sample of n = 20 from an unknown population.What is the df value for the t statistic?

Accepted Answer

A) 19 
B) 20 
C) 21 
D) Cannot be determined from the information given 
A) 19 
B) 20 
C) 21 
D) Cannot be determined from the information given

Question 14

A research report states "t(15)= 2.31,p < .05." For this study,the sample had n = 16 scores.

Accepted Answer

A) True 
 B)False

Question 15

When n is small (less than 30),how does the shape of the t distribution compare to the normal distribution?

Accepted Answer

A) It is almost perfectly normal. 
B) It is flatter and more spread out than the normal distribution. 
C) It is taller and narrower than the normal distribution. 
D) There is no consistent relationship between the t distribution and the normal distribution. 
A) It is almost perfectly normal. 
B) It is flatter and more spread out than the normal distribution. 
C) It is taller and narrower than the normal distribution. 
D) There is no consistent relationship between the t distribution and the normal distribution.

Question 16

On average,what value is expected for the t statistic when the null hypothesis is true?

Accepted Answer

A) t = 0 
B) t = 1 
C) t = 1.96 
D) t > 1.96 
A) t = 0 
B) t = 1 
C) t = 1.96 
D) t > 1.96

Question 17

A sample of n = 9 participants is obtained from a population with μ = 29,and a treatment is administered to the individuals in the sample.After treatment,the scores for the nine participants are as follows: 23,33,26,28,30,26,27,25,25.
a. Are the data sufficient to conclude that the treatment has a significant effect? Use a two-tailed test with α = .05.
b. Are the data sufficient to conclude that the treatment significantly decreased scores? Use a one-tailed test with α = .05.

Accepted Answer

a.M = 27 and SS = 72.The stand

Question 18

A researcher selects a sample from a population with μ = 30 and uses the sample to evaluate the effect of a treatment.After treatment,the sample has a mean of M = 32 and a variance of s² = 6.Which of the following would definitely increase the likelihood of rejecting the null hypothesis?

Accepted Answer

A) Increase the sample size 
B) Increase the sample mean 
C) Decrease the sample variance 
D) All of the other options will increase the likelihood of rejecting the null hypothesis. 
A) Increase the sample size 
B) Increase the sample mean 
C) Decrease the sample variance 
D) All of the other options will increase the likelihood of rejecting the null hypothesis.

Question 19

A sample of n = 25 scores has a mean of M = 40 and a standard deviation of s = 10.What is the estimated standard error for the sample mean?

Accepted Answer

A) 4 
B) 2 
C) 2.5 
D) 1 
A) 4 
B) 2 
C) 2.5 
D) 1

Question 20

When the population variance or standard deviation is not known,you must use a t statistic instead of a z-score for a hypothesis test.

Accepted Answer

A) True 
 B)False

A sample of n = 16 scores has a mean of M = 65 and an estimated standard error of 2 points.What is the sample variance?

If the 90% confidence interval for µ is from 40 to 50,then the sample mean is M = 45.

A hypothesis test with a sample of n = 25 participants produces a t statistic of t = +2.53.Assuming a one-tailed test with the critical region in the right-hand tail,what is the correct decision?

If other factors are held constant,what is the effect of increasing the sample size?

What value is estimated with a confidence interval using the t statistic?

A researcher selects a sample from a population with a mean of µ = 40 and administers a treatment to the individuals in the sample.If the treatment is expected to decrease scores,which of the following is the correct statement of the null hypothesis for a one-tailed test?

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

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?

Two samples are selected from a population,and a treatment is administered to the samples.If both samples have the same mean and the same variance,you are more likely to find a significant treatment effect with a sample of n = 100 than with a sample of n = 4.

A sample is selected from a population with μ = 46,and a treatment is administered to the sample.After treatment,the sample mean is M = 48 with a sample variance of s² = 16.Based on this information,what is the value of Cohen's d?

If other factors are held constant,what is the effect of increasing the sample variance?

What is the sample variance and the estimated standard error for a sample of n = 9 scores with SS = 72?

A researcher conducts a hypothesis test using a sample of n = 20 from an unknown population.What is the df value for the t statistic?

A research report states "t(15)= 2.31,p < .05." For this study,the sample had n = 16 scores.

When n is small (less than 30),how does the shape of the t distribution compare to the normal distribution?

On average,what value is expected for the t statistic when the null hypothesis is true?

A researcher selects a sample from a population with μ = 30 and uses the sample to evaluate the effect of a treatment.After treatment,the sample has a mean of M = 32 and a variance of s² = 6.Which of the following would definitely increase the likelihood of rejecting the null hypothesis?

A sample of n = 25 scores has a mean of M = 40 and a standard deviation of s = 10.What is the estimated standard error for the sample mean?

When the population variance or standard deviation is not known,you must use a t statistic instead of a z-score for a hypothesis test.

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

A sample of n = 16 scores has a mean of M = 65 and an estimated standard error of 2 points.What is the sample variance?

If the 90% confidence interval for µ is from 40 to 50,then the sample mean is M = 45.

A hypothesis test with a sample of n = 25 participants produces a t statistic of t = +2.53.Assuming a one-tailed test with the critical region in the right-hand tail,what is the correct decision?

If other factors are held constant,what is the effect of increasing the sample size?

What value is estimated with a confidence interval using the t statistic?

A researcher selects a sample from a population with a mean of µ = 40 and administers a treatment to the individuals in the sample.If the treatment is expected to decrease scores,which of the following is the correct statement of the null hypothesis for a one-tailed test?

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

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?

Two samples are selected from a population,and a treatment is administered to the samples.If both samples have the same mean and the same variance,you are more likely to find a significant treatment effect with a sample of n = 100 than with a sample of n = 4.

A sample is selected from a population with μ = 46,and a treatment is administered to the sample.After treatment,the sample mean is M = 48 with a sample variance of s² = 16.Based on this information,what is the value of Cohen's d?

If other factors are held constant,what is the effect of increasing the sample variance?

What is the sample variance and the estimated standard error for a sample of n = 9 scores with SS = 72?

A researcher conducts a hypothesis test using a sample of n = 20 from an unknown population.What is the df value for the t statistic?

A research report states "t(15)= 2.31,p < .05." For this study,the sample had n = 16 scores.

When n is small (less than 30),how does the shape of the t distribution compare to the normal distribution?

On average,what value is expected for the t statistic when the null hypothesis is true?

A researcher selects a sample from a population with μ = 30 and uses the sample to evaluate the effect of a treatment.After treatment,the sample has a mean of M = 32 and a variance of s² = 6.Which of the following would definitely increase the likelihood of rejecting the null hypothesis?

A sample of n = 25 scores has a mean of M = 40 and a standard deviation of s = 10.What is the estimated standard error for the sample mean?

When the population variance or standard deviation is not known,you must use a t statistic instead of a z-score for a hypothesis test.

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