Question 1

If other factors are held constant, which set of sample characteristics is most likely to reject a null hypothesis stating that $\mu$ = 80?

Accepted Answer

A) M = 85 and small sample variance 
B) M = 85 and large sample variance 
C) M = 90 and small sample variance 
D) M = 90 and large sample variance

Question 2

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

Question 3

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

Accepted Answer

A) True 
 B)False

Question 4

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

Question 5

If other factors are held constant, which set of sample characteristics is most likely to produce a significant t statistic?

Accepted Answer

A) n = 25 with s2 = 100 
B) n = 25 with s2 = 400 
C) n = 100 with s2 = 100 
D) n = 100 with s2 = 400

Question 6

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 7

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

Accepted Answer

A) n = 25 with s2 = 100 
B) n = 25 with s2 = 400 
C) n = 100 with s2 = 100 
D) n = 100 with s2 = 400

Question 8

With α = .01 the two-tailed critical region for a t test using a sample of n = 16 subjects would have boundaries of ______.

Accepted Answer

A) t = ±2.602 
B) t = ±2.583 
C) t = ±2.947 
D) t = ±2.921

Question 9

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

Accepted Answer

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

Question 10

In a hypothesis test, a large value for the sample variance increases the likelihood that you will find a significant treatment effect.

Accepted Answer

A) True 
 B)False

Question 11

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) Non of the other options explains the extra variability for t statistics.

Question 12

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

Accepted Answer

A) True 
 B)False

Question 13

With α = .05 and df = 8, the critical values for a two-tailed t test are t = ±2.306.Assuming all other factors are held constant, if the df value were increased to df = 20, what would happen to the critical values for t?

Accepted Answer

A) They would increase (move farther from zero). 
B) They would decrease (move closer to zero). 
C) They would stay the same. 
D) not enough information to answer

Question 14

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)

Question 15

In order to estimate a population mean with a confidence interval, you first must estimate a range of values for t.

Accepted Answer

A) True 
 B)False

Question 16

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.

Question 17

A sample with a mean of M = 40 and a variance of s2 = 20 has an estimated standard error of 2 points.How many scores are in the sample?

Accepted Answer

A) 4 
B) 5 
C) 10 
D) 25

Question 18

In general, the larger the value of the sample variance, the greater the likelihood of rejecting the null hypothesis.

Accepted Answer

A) True 
 B)False

Question 19

A sample of n = 4 scores has SS = 48.What is the estimated standard error for the sample mean?

Accepted Answer

A) 1 
B) 2 
C) 4 
D) 16

Question 20

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.

Exam 9: Introduction to the T Statistic

If other factors are held constant, which set of sample characteristics is most likely to reject a null hypothesis stating that $\mu$ = 80?

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

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

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

If other factors are held constant, which set of sample characteristics is most likely to produce a significant t statistic?

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.

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

With α = .01 the two-tailed critical region for a t test using a sample of n = 16 subjects would have boundaries of ______.

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

In a hypothesis test, a large value for the sample variance increases the likelihood that you will find a significant treatment effect.

Why are t statistics more variable than z-scores.

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

With α = .05 and df = 8, the critical values for a two-tailed t test are t = ±2.306.Assuming all other factors are held constant, if the df value were increased to df = 20, what would happen to the critical values for t?

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?

In order to estimate a population mean with a confidence interval, you first must estimate a range of values for t.

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

A sample with a mean of M = 40 and a variance of s² = 20 has an estimated standard error of 2 points.How many scores are in the sample?

In general, the larger the value of the sample variance, the greater the likelihood of rejecting the null hypothesis.

A sample of n = 4 scores has SS = 48.What is the estimated standard error for the sample mean?

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?

Exam 9: Introduction to the T Statistic

If other factors are held constant, which set of sample characteristics is most likely to reject a null hypothesis stating that μ\muμ = 80?

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

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

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

If other factors are held constant, which set of sample characteristics is most likely to produce a significant t statistic?

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.

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

With α = .01 the two-tailed critical region for a t test using a sample of n = 16 subjects would have boundaries of ______.

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

In a hypothesis test, a large value for the sample variance increases the likelihood that you will find a significant treatment effect.

Why are t statistics more variable than z-scores.

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

With α = .05 and df = 8, the critical values for a two-tailed t test are t = ±2.306.Assuming all other factors are held constant, if the df value were increased to df = 20, what would happen to the critical values for t?

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?

In order to estimate a population mean with a confidence interval, you first must estimate a range of values for t.

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

A sample with a mean of M = 40 and a variance of s2 = 20 has an estimated standard error of 2 points.How many scores are in the sample?

In general, the larger the value of the sample variance, the greater the likelihood of rejecting the null hypothesis.

A sample of n = 4 scores has SS = 48.What is the estimated standard error for the sample mean?

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?

If other factors are held constant, which set of sample characteristics is most likely to reject a null hypothesis stating that $\mu$ = 80?

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 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?

A sample with a mean of M = 40 and a variance of s² = 20 has an estimated standard error of 2 points.How many scores are in the sample?