Question 1

The research hypothesis states that the
A) independent variable had no effect.
B) independent variable did have an effect.
C) dependent variable had no effect.
D) dependent variable did have an effect.

Accepted Answer

The research hypothesis is typically a statement predicting that the independent variable (the one being manipulated) will have an effect on the dependent variable (the one being measured). Therefore, option B is the correct choice.

Question 2

When a researcher _____ the probability of making a Type I error,she _____ the probability of making a Type II error.
A) increases;increases
B) decreases;increases
C) decreases;decreases
D) decreases;does not affect

Accepted Answer

When the researcher decreases the probability of making a Type I error (by choosing a lower alpha level, for example), she increases the probability of making a Type II error. This is known as the trade-off between Type I and Type II errors.

Question 3

Negative results are problematical because they
A) are difficult to interpret.
B) are less important.
C) disprove the theory you are trying to support.
D) are difficult to analyze statistically.

Accepted Answer

A

Question 4

Sandra has developed a program designed to increase reading comprehension scores in 6^th graders.She randomly selects three students and has them participate in her program.When she compares the mean score from the students who completed her program to three students who did not participate in the program,she finds no significant difference between their mean scores.What is most likely the reason for the non-significant finding? A) Too strong of a manipulation B) The use of 6^th grade children C) A small sample size D) A true research hypothesis

Accepted Answer

A small sample size can limit the power of the statistical analysis and increase the likelihood of finding no significant difference. With only three students in the study, there may not be enough data to detect a true effect of the program on reading comprehension scores.

Question 5

A researcher wants to test the research hypothesis that the mean rating of guilt will be higher for unattractive defendants than for attractive defendants.The appropriate statistical test would be the
A) Pearson r.
B) 2-tailed t-test.
C) 1 tailed t-test.
D) chi-square.

Accepted Answer

A 1-tailed t-test would be appropriate to test this research hypothesis as the researcher has a directional hypothesis (i.e., that the mean rating of guilt will be higher for unattractive defendants) and wants to determine if there is a significant difference in guilt ratings between the two groups. Other options (Pearson r, chi-square) are not appropriate for testing this type of hypothesis, and a 2-tailed t-test would not be as powerful as a 1-tailed t-test in this case.

Question 6

In a multiple-choice question with four alternatives,if the null hypothesis is correct,the probability of a person choosing the correct answer is approximately
A) 1 out of 4.
B) 2 out of 4.
C) 3 out of 4.
D) 4 out of 4.

Accepted Answer

If the null hypothesis is correct, then all four alternatives are equally likely to be the correct answer. Therefore, the probability of choosing the correct answer is 1 out of 4 (or 25%).

Question 7

Which significance level would minimize the probability of a Type I error?
A) .25
B) .10
C) .05
D) .01

Accepted Answer

A lower significance level minimizes the probability of a Type I error. Among the options given, 0.01 is the lowest significance level and therefore the best choice.

Question 8

The appropriate statistical test for interval or ratio level data derived from measuring the dependent variable (for more than two groups)is the
A) t-test.
B) Pearson correlation.
C) chi-square.
D) F test (analysis of variance).

Accepted Answer

The F test, also known as analysis of variance (ANOVA), is the appropriate statistical test for interval or ratio level data derived from measuring the dependent variable for more than two groups. It is used to determine whether there are statistically significant differences between the means of three or more groups. The t-test is appropriate for comparing the means of two groups, the Pearson correlation is used to determine the relationship between two continuous variables, and the chi-square test is used for categorical data.

Question 9

How do you calculate the systematic variance?
A) Find the deviation of the individual scores from the group mean.
B) Find the deviation of the group means from the grand mean.
C) Find the deviation of error variance from the group mean.
D) Find the deviation of error variance from the grand mean.

Accepted Answer

Systematic variance is the variance that is caused by the manipulated independent variable. To calculate it, we need to find the deviation of the group means from the grand mean. This is because we are interested in the differences between the groups that result from the manipulation of the independent variable. Option A is incorrect because it refers to the calculation of individual scores which is not relevant to the calculation of systematic variance. Options C and D are incorrect because they refer to the deviation of error variance which is not the same as systematic variance.

Question 10

The null hypothesis
A) is used because it is a very precise statement.
B) is rejected when there is a high probability that the obtained results are due to random error.
C) does not allow us to know the probability of the outcome of the study occurring.
D) is statistically significant if it can be accepted.

Accepted Answer

The null hypothesis is a precise statement that assumes no effect or no difference, and it is used as a basis for statistical testing.

Question 11

The desired probability of correctly rejecting the null hypothesis is the
A) Type I error.
B) Type II error.
C) effect size of the test.
D) power of the test.

Accepted Answer

The desired probability of correctly rejecting the null hypothesis is the power of the test. Option A is incorrect because Type I error refers to rejecting the null hypothesis when it is true. Option B is incorrect because Type II error refers to failing to reject the null hypothesis when it is false. Option C is incorrect because effect size refers to the magnitude of the difference between the null and alternative hypotheses, and does not relate to the probability of correctly rejecting the null hypothesis.

Question 12

Error variance is the deviation of
A) the individual scores about the group mean.
B) the group means about the grand mean.
C) error variance about the group mean.
D) error variance about the grand mean

Accepted Answer

Error variance refers to the variability in observed scores that cannot be attributed to the variables being studied, essentially capturing the deviations of individual scores from their group mean.

Question 13

Brandon found no significant difference in amount of money spent on entertainment between students who live on versus off campus.Based on this finding,Brandon would
A) fail to reject the null.
B) reject the null.
C) accept a Type I error.
D) reject a Type I error.

Accepted Answer

Since there was no significant difference found, Brandon would fail to reject the null hypothesis.

Question 14

Juan wants to test the hypothesis that the mean amount of sales dollars will vary between Oak Ridge,Oak Wood,and Oak Park shopping malls.The appropriate statistical test would be the
A) Mann-Whitney U.
B) t-test.
C) F-test.
D) Pearson r.

Accepted Answer

The appropriate statistical test for testing the hypothesis that the mean amount of sales dollars will vary between Oak Ridge, Oak Wood, and Oak Park shopping malls would be an ANOVA F-test. This test is used to compare the means of three or more groups and determine if there is a significant difference between them. The Mann-Whitney U test is used to compare two independent groups, the t-test is used to compare the means of two groups, and Pearson r is used to measure the strength of a linear relationship between two continuous variables.

Question 15

_____ is a type of correlation coefficient that indicates the _____ the effect of the independent variable.
A) T ;difference in
B) T ;magnitude of
C) Effect size r;difference in
D) Effect size r;magnitude of

Accepted Answer

Effect size r is a type of correlation coefficient that indicates the magnitude of the effect of the independent variable, making option D the correct choice. Options A and C are incorrect because T is not a type of correlation coefficient used to indicate the effect of the independent variable. Option B is incorrect because it only partially completes the sentence and does not specify what type of correlation coefficient is being referred to.

Question 16

A student is interested in the effect of environmental condition on task performance.She has participants complete a series of math problems under different temperatures (cold,warm,hot)and noise condition (quiet,noisy).The most appropriate test to analyze the data would be a(n)
A) t-test.
B) Pearson r.
C) chi-square.
D) F-test.

Accepted Answer

The most appropriate test to analyze the data would be a two-way ANOVA with temperature and noise condition as the independent variables and task performance as the dependent variable. The F-test is used in ANOVA to determine if there is a significant difference between the means of multiple groups. The other options (t-test, Pearson r, chi-square) are not appropriate for analyzing this type of data.

Question 17

The expected value of t if the null hypothesis is true would
A) equal 1.
B) equal 0.
C) depend on the degrees of freedom.
D) vary depending on the alpha level.

Accepted Answer

If the null hypothesis is true, then the difference between the sample mean and the hypothesized population mean is zero. Therefore, the expected value of t, which is computed using this difference, would also be zero.

Question 18

Which one of the following accurately describes the relationship between concepts?
A) Systematic variance = error variance
B) Error variance = between-groups variance
C) Between-groups variance = systematic variance
D) Systematic variance = within-group variance

Accepted Answer

Between-groups variance is attributed to the effects of different treatments or conditions in an experiment, which is what systematic variance represents. Systematic variance is the portion of variation in observations that is due to the independent variable, distinguishing it from random or error variance.

Question 19

The appropriate statistical test for nominal level data derived from measuring the dependent variable (for two groups)is
A) t.
B) Pearson correlation.
C) chi-square.
D) analysis of variance.

Accepted Answer

The appropriate statistical test for nominal level data derived from measuring the dependent variable for two groups is chi-square. Chi-square is a non-parametric test used to determine if there is a significant difference between the expected frequencies and the observed frequencies in one or more categories. It is commonly used to compare categorical data between two groups.

Question 20

Your lab group must choose a significance test to determine if the mean scores of two groups are significantly different.The appropriate test is a(n)
A) t test.
B) Mann-Whitney U.
C) chi-square.
D) analysis of variance.

Accepted Answer

The t test is used to test the significant difference between the means of two groups. As the question specifically asks for a test to compare mean scores of two groups and doesn't mention any categorical variables, the t test would be the best choice.

Quiz 13: Understanding Research Results: Statistical-Inference Basics

The research hypothesis states that the

When a researcher _ the probability of making a Type I error,she _ the probability of making a Type II error.

Negative results are problematical because they

A researcher wants to test the research hypothesis that the mean rating of guilt will be higher for unattractive defendants than for attractive defendants.The appropriate statistical test would be the

In a multiple-choice question with four alternatives,if the null hypothesis is correct,the probability of a person choosing the correct answer is approximately

Which significance level would minimize the probability of a Type I error?

The appropriate statistical test for interval or ratio level data derived from measuring the dependent variable (for more than two groups) is the

How do you calculate the systematic variance?

The null hypothesis

The desired probability of correctly rejecting the null hypothesis is the

Error variance is the deviation of

Brandon found no significant difference in amount of money spent on entertainment between students who live on versus off campus.Based on this finding,Brandon would

Juan wants to test the hypothesis that the mean amount of sales dollars will vary between Oak Ridge,Oak Wood,and Oak Park shopping malls.The appropriate statistical test would be the

_ is a type of correlation coefficient that indicates the _ the effect of the independent variable.

A student is interested in the effect of environmental condition on task performance.She has participants complete a series of math problems under different temperatures (cold,warm,hot) and noise condition (quiet,noisy) .The most appropriate test to analyze the data would be a(n)

The expected value of t if the null hypothesis is true would

Which one of the following accurately describes the relationship between concepts?

The appropriate statistical test for nominal level data derived from measuring the dependent variable (for two groups) is

Your lab group must choose a significance test to determine if the mean scores of two groups are significantly different.The appropriate test is a(n)