A random sample of n = 4 scores is selected from a population. Which of the following distributions definitely will be normal?

A. The scores in the sample will definitely form a normal distribution.

B. The scores in the population will definitely form a normal distribution

C. The distribution of sample means will definitely form a normal distribution.

D. Neither the sample, the population, nor the distribution of sample means will definitely be normal.

A hypothesis test is:

A. a descriptive technique that allows researchers to describe a sample

B. a descriptive technique that allows researchers to describe a population

C. an inferential technique that uses the data from a sample to draw inferences about a population

D. an inferential technique that uses information about a population to make predictions about a sample

The null hypothesis:

A. states that the treatment has no effect

B. is denoted by the symbol H with 1 in subscript

C. is always stated in terms of sample statistics

D. All of the other choices are correct

The z-score boundaries for the critical region are determined by

A. the null hypothesis

B. the sample data

C. the size of the standard error

D. the alpha level

By definition, a Type I error is:

A. rejecting a false alternative hypothesis

B. rejecting a false null hypothesis

C. rejecting a true null hypothesis

D. rejecting a true alternative hypothesis

A Type II error is defined as:

A. rejecting a false null hypothesis

B. rejecting a true null hypothesis

C. failing to reject a false null hypothesis

D. failing to reject a true null hypothesis

Which alpha level provides the greatest risk of committing a Type I error?

A. .01

B. .05

C. .10

D. .025

Which of the following is a fundamental difference between the t statistic and a z-score?

A. The t statistic uses the sample mean in place of the population mean.

B. The t statistic uses the sample variance/SD in place of the population variance/SD.

C. The t statistic computes the standard error by dividing the standard deviation by n - 1 instead of dividing by n.

D. All of the above are differences between t and z

For a population with mean = 80 and standard deviation = 10, what is the z-score corresponding to X = 95?

A. 0.25

B. 0.75

C. 1

D. 1.5

An introductory psychology class has 9 freshman males, 15 freshman females, 8 sophomore males, and 12 sophomore females. If one student is randomly selected from this class, what is the probability of getting a sophomore?

A. 8/24

B. 20/24

C. 20/44

D. 14/44

An introductory psychology class has 9 freshman males, 15 freshman females, 8 sophomore males, and 12 sophomore females. A random sample of n = 2 students is selected from the class. If the first student in the sample is a male, what is the probability that the second student will also be a male?

A. 16/43

B. 16/44

C. 17/43

D. 17/44

A vertical line is drawn through a normal distribution at z = -1.00. The line separates the distribution into two sections. What percentage of the distribution is in the larger section?

A. 75%

B. 84.13%

C. -84.13%

D. 15.87%

For a population with mean = 80 and std. deviation = 12, what is the z-score corresponding to X = 92?

A. 12

B. 0.5

C. 0.75

D. 1

For a population with mean = 100 and std. deviation = 20, what is the X value corresponding to z = 0.25?

A. 105

B. 110

C. 115

D. 120

A sample of n = 4 scores is selected from a population with mean = 50 and std. deviation = 12. If the sample mean is M = 56, what is the z-score for this sample mean?

A. 0.5

B. 1

C. 2

D. 4

What proportion of a normal distribution is located in the tail beyond a z-score of z = 1.00?

A. 0.8413

B. 0.1587

C. 0.3413

D. 0.3174

A researcher administers a treatment to a sample of n = 25 participants and uses a single sample t-test to evaluate the effect of the treatment. The hypothesis test produces a t-test of t = 2.37. Assuming that the researcher is using a two-tailed test, what decision should be made?

A. The researcher should reject the null hypothesis with alpha = .05 but not with alpha = .01.

B. The researcher should reject the null hypothesis with both alpha = .05 and alpha = .01.

C. The researcher should fail to reject the null hypothesis with either alpha = .05 or alpha = .01.

D. Cannot answer without additional information.

A researcher administers a treatment to a sample of n = 15 participants and uses a single sample t-test to evaluate the effect of the treatment. The hypothesis test produces a t-test of t = 3.01. Assuming that the researcher is using a two-tailed test, what decision should be made?

A. The researcher should reject the null hypothesis with alpha = .05 but not with alpha = .01.

B. The researcher should reject the null hypothesis with both alpha = .05 and alpha = .01.

C. The researcher should fail to reject the null with either alpha = .05 or alpha = .01.

D. Cannot answer without additional information.