Psy 10 Final

A set of n = 15 pairs of X and Y scores has SSX = 10, SSY = 40, and SSxy = 30. What is the slope for the regression equation for predicting Y from X? a) 30/10 b) 40/10 c) 10/40 d) 10/30

a) 30/10

A researcher compares differences in positivity between participants in a low-, middle-, or upper middle-class family. If she observes 15 participants in each group, then what are the degrees of freedom for the one-way between-subjects ANOVA? a) (3, 43) b) (2, 42) c) (3, 12) d) (2, 12)

b) (2, 42)

On average, what value is expected for the F-ratio if the null hypothesis is true? a) N - k b) 1.00 c) k - 1 d) 0

b) 1.00

The t distribution is similar to the z distribution except a) it is associated with greater variability b) all of these c) it is characterized by "thicker" tails compared with the z distribution d) it is associated with scores being more likely in the tails of the distribution

b) all of these

When comparing more than two group means, should you use an analysis of variance rather than using several t tests, and if so, why? a) No. There is no advantage to using an analysis of variance rather than several t tests. b) Yes. Using several t tests increases the risk of a Type II error. c) Yes. Using several t tests increases the risk of a Type I error. d) Yes. The analysis of variance is more likely to detect a treatment effect.

c) Yes. Using several t tests increases the risk of a Type I error.

An analysis of variance produces SSbetween = 40 and MSbetween = 20. In this analysis, how many groups are being compared? a) 4 b) 20 c) 2 d) 3

d) 3

For a two-tailed hypothesis test evaluating a Pearson correlation, what is stated by the null hypothesis? a) The population correlation is zero. b) There is a non-zero correlation for the sample. c) The sample correlation is zero. d) There is a non-zero correlation for the general population.

a) The population correlation is zero.

State the critical value(s) for a t test using a two-tailed test at a .05 level of significance: t(20) a) ±2.086 b) ±0.687 c) ±1.725 d) ±2.093

a) ±2.086

What is the pooled variance for the following two independent samples? Sample 1: n = 8 and SS = 168 Sample 2: n = 6 and SS = 120 a) 20.57 b) 27 c) 24 d) 7

c) 24

In a sample of 28 participants, a researcher estimates the 95% CI for a sample with a mean of 1.5 and an estimated standard error of 0.3. What is the confidence interval at this level of confidence? a) There is not enough information to answer this question. b) 95% CI (1.2, 1.8) c) 95% CI (0.9, 2.1) d) 95% CI (1.0, 2.0)

c) 95% CI (0.9, 2.1)

The test statistic for a related-samples t test makes tests concerning a single sample of ______. a) raw scores b) original data c) difference scores d) participant scores

c) difference scores

A professor compares scores on a competency exam among students at two times during a single semester. What type of t test is most appropriate for this study? a) There is not enough information to answer this question. b) two-independent-sample t test c) related-samples t test d) one-sample t test

c) related-samples t test

A researcher measures the relationship between narcissism and willingness to help. If SSXY = 240, SSX = 320, and SSY = 410, then what is the value of the correlation coefficient? a) .002 b) .02 c) .69 d) .66

d) .66

A researcher computes a 2 × 4 between-subjects ANOVA. What are the degrees of freedom for Factor B for this study? a) 8 b) 4 c) 2 d) 3

d) 3

The source of variability associated with error variance in the one-way between-subjects ANOVA is called ______. a) between-groups variability b) degrees of freedom c) both between-groups and within-groups variability d) within-groups variability

d) within-groups variability

A significant slope means that ________ a) the slope is not equal to 0 in the population. b) the slope is positive. c) the correlation is positive. d) there is a significant relationship between X and Y in the sample.

a) the slope is not equal to 0 in the population.

An analysis of variance produces SSbetween = 30, SSwithin = 60, and an F-ratio with df = 2 and 15. For this analysis, what is the F-ratio? a) 60/30 = 2.00 b) 15/4 = 3.75 c) 30/60 = 0.50 d) 4/15 = 0.27

b) 15/4 = 3.75

In a sample of 20 participants, a researcher estimates the 95% CI for a sample with a mean of 5.4 and an estimated standard error of 1.6. What is the upper confidence limit for this interval? a) 7.0 b) 8.8 c) 3.8 d) 2.1

b) 8.8

What is stated by the null hypothesis (H0) for an ANOVA? a) At least one of the population means is different from another mean. b) There are no differences between any of the population means. c) All of the population means are different from each other. d) The estimate is significant.

b) There are no differences between any of the population means.

Which of the following indicates the strongest correlation? a) r = +0.88 b) r = -0.90 c) r = -0.57 d) r = +0.78

b) r = -0.90

A set of n = 5 pairs of X and Y values has SSX = 16, SSY = 4 and SSxy = 2. For these data, the Pearson correlation is ____. a) r = 2/64 b) r = 2/8 c) r = 8/8 d) r = 64/8

b) r = 2/8

The difference between your actual value and predicted value in a least squares regression is _______ a) intercept b) residual c) regression coefficient d) standard error

b) residual

For an analysis of variance, the term "two-way" refers to ______. a) the number of statistical tests in the design b) the number of factors in the design c) the number of ways that the data can be analyzed d) the direction that traffic should follow on a road

b) the number of factors in the design

A researcher conducts two t tests. Test 1 is a two-tailed test with a smaller sample size at a .05 level of significance. Test 2 is a two-tailed test with a larger sample size at a .05 level of significance. What do you know about the degrees of freedom for each test? a) Test 1 is associated with larger degrees of freedom. b) It depends; there is not enough information to answer this question. c) Test 2 is associated with larger degrees of freedom. d) Each test is associated with the same degrees of freedom.

c) Test 2 is associated with larger degrees of freedom.

What would the scatterplot show for data that produce a correlation of +0.88? a) points clustered close to a line that slopes down to the right b) points widely scattered around a line that slopes down to the right c) points clustered close to a line that slopes up to the right d) points widely scattered around a line that slopes up to the right

c) points clustered close to a line that slopes up to the right

The results from a research study indicate that adolescents who watch more violent content on television also tend to engage in more violent behavior than their peers. The correlation between amount of TV violent content and amount of violent behavior is an example of a ____. a) correlation near zero b) negative correlation c) positive correlation d) correlation near one

c) positive correlation

An independent-samples study with n = 6 in each of the two samples, produces a sample mean difference of 4 points and a pooled variance of 12. What is the value for the t statistic? a) 4/8 b) 2 c) 1 d) 4/6

b) 2

The numerical value for a correlation can ____. a) never be greater than 1.00 b) never be less than 1.00 c) be greater than 1.00 and can be less than -1.00 d) never be greater than 1.00 and can never be less than -1.00

d) never be greater than 1.00 and can never be less than -1.00