extra credit questions

For an independent-samples t test, there were 14 participants in Group 1 and 17 participants in Group 2. The critical cutoffs for a two-tailed test with alpha of 0.05 are: - -2.043 and 2.043 - -2.030 and 2.030 - -2.045 and 2.045 - -2.049 and 2.049

-2.045 and 2.045

A two-way study with two levels of factor A and three levels of factor B uses a separate group of n = 5 participants in each treatment condition. How many participants are needed for the entire study?​ - 10 - 5 - 30 - 25

30

A linear regression equation has b = 3 and a = - 6. What is the predicted value of Y for X = 4? - This cannot be determined without additional information. - -2 - -21 - 6

6

For the regression equation, Y' = - 3 + 2X, if the mean for X is 5, what is the mean for Y? - 5 - 2 - 7 - 4

7

Which of the following not used in an F ratio for the two-way ANOVA? - MS_within groups - MS_AxB - MS_between groups - MS_A

MS_between groups

In a line graph showing the results from a two-way design, the levels of factor B are presented on the X-axis and separate lines are used to display the means for A1 and A2. If the points on the line for A1 are consistently five points higher than the corresponding point on the line for A2, what pattern of results is indicated?​ - an indication of an A-effect but no indication of an interaction - an indication of an A-effect and an indication of an interaction - no indication of an A-effect but an indication of an interaction - no indication of an A-effect and no indication of an interaction

an indication of an A-effect but no indication of an interaction

Why can't a researcher just run multiple t tests when the independent variable has more than two levels? - as you run more statistical tests, it becomes harder and harder to reject the null hypothesis. - as you run more statistical tests, the probability that you will make a Type I error in one of the tests increases. - as you run more statistical tests, the probability that you will make a Type II error in one of those tests increases. - as you run more statistical tests, you lose degrees of freedom.

as you run more statistical tests, the probability that you will make a Type I error in one of the tests increases.

If there is a positive correlation between X and Y then in the regression equation, Y' = a+ bX, ____. - b > 0 - b < 0 - a > 0 - a < 0

b > 0

A researcher notes that the variability attributed to difference between group means is quite large. Which source of variation is the researcher referring to? - between-persons - within-groups - between-groups - error

between-groups

As the degrees of freedom increase, the similarity between t and z distributions . - cannot be determined - decreases - increases - remains the same

increases

What is indicated by a positive value for a correlation? - increases in X tend to be accompanied by increases in Y. - increases in X tend to be accompanied by decreases in Y. - a much stronger relationship exists than if the correlation were negative. - a much weaker relationship exists than if the correlation were negative.

increases in X tend to be accompanied by increases in Y.

In a two-way ANOVA a main effect is defined as the ____.​ - difference between the largest treatment mean and the smallest treatment mean - mean differences among all treatment conditions - mean differences among the levels of one factor - mean difference between the two factors

mean differences among the levels of one factor

The number of degrees of freedom for the t statistic for independent samples is equal to: - 2^n - n - 1 - n - 2 - n1 + n2 - 2

n1 + n2 - 2

For which of the following correlations would the data points be most widely scattered around the regression line? - r = 0.10 - r = 0.80 - r = 0.99 - r = 0.50

r = 0.10

A researcher assigns 21 adolescents to rate the likability of a person described in a vignette as having one of three personality traits. An equal number of participants are assigned to each group. If Fobt = 4.08 for this study, then what was the decision at a .05 level of significance for a one-way between-subjects ANOVA? - retain the null hypothesis - reject the null hypothesis - There is not enough information to answer this question.

reject the null hypothesis

A researcher records the time it takes (in seconds) for participants to respond (by pressing a key) to a familiar and an unfamiliar word flashed onto a computer screen. In this study, the difference in response time for each participant is compared. The type of design described here is called a ______. - single-sample design - matched-samples design - repeated-measures design - independent-samples design

repeated-measures design

A post-hoc test is warranted when: - we reject the null hypothesis when performing an independent-groups t test. - we have an a priori prediction about which group means will differ. - we fail to reject the null hypothesis in an ANOVA. - the F is significant and there are more than two groups.

the F is significant and there are more than two groups.

Two variables are said to interact when ____.​ - both variables produce a change in the subjects' scores - both variables are equally influenced by a third factor - the two variables are differentially affected by a third variable - the effect of one independent variable depends on the levels of the second variable

the effect of one independent variable depends on the levels of the second variable

A t test is used in situations where: - the alternative hypothesis is directional only - the omega must be estimated from sample information - the omega is known - the alternative hypothesis is non-directional only

the omega must be estimated from sample information

The F ratio increases as . - the variability between groups decreases relative to the variability within groups - the total variability decreases - the total variability increases - the variability between groups increases relative to the variability within groups

the variability between groups increases relative to the variability within groups