hailey - exam 2 conceptual quant methods

When both the independent and dependent variables are interval/ratio level, which statistical test should be used?

A. paired-samples t

B. independent samples t

C. Pearson's r

D. either A or C, because the same people (or items) are being measured twice.

C. Pearson's r

Why is the term 2r(SEM1)(SEM2) not included in the independent samples t-test?

A. Because we only use SEM1 in the independent samples t-test

B. Because the relationship in an independent samples t-test is assumed to be non-linear

C. Because the r is assumed to be 0 in the independent samples t-test

D. Because the denominator in the independent samples t-test underestimates the estimated standard error the difference

C. Because the r is assumed to be 0 in the independent samples t-test

The term -2r(SEM1)(SEM2) in the paired samples t-test causes the t-ratio to be ________ than it would if the term were excluded.

A. larger

B. smaller

C. more biased with respect to the population parameter

D. less biased with respect to the population parameter

C. more biased with respect to the population parameter

With respect to the paired-samples t-test, as the size of the r increases, the t-ratio _____ making it ________ to reject the null hypothesis.

A. increases; less likely

B. increases; more likely

C. decreases; less likely

D. remains the same; equally likely

B. increases; more likely

If the Pearson's r between variables X and Y is -.50, how much of variance in Y can be predicted by X?

A. 50%

B. 25%

C. none - negative correlations do not permit you to explain variance in a criterion variable

D. you cannot tell from the Pearson's r how much variance in Y can be predicted from X.

B. 25%

Which of the following, if any, is true with respect to Pearson's r?

A. Either of the variables must be ordinal

B. The ranges of values for X and Y can be no greater than + or minus 1 SD of their means.

C. The form of the relationship between X and Y can be non-linear

D. None of the above are true

D. None of the above are true

Which of the following is used in determining the degrees of freedom between in the 1 way ANOVA?

A. the number of independent variables

B. the number of subjects or scores

C. the number of levels of the IV

D. none of the above

C. the number of levels of the IV

In the F statistic, the sum of squares between is influenced by

A. variation within each group in the design

B. differences between each group mean and the grand mean

C. the number of groups (or means being compared) in the study

D. A and B

E. B and C

E. B and C

In an experiment, the numerator in the F statistic is a measure of

A. the effect of the independent variable on the dependent variable

B. the effect of individual differences among subjects on the dependent variable

C. the effect of the dependent variable on the independent variable

D. the effect of the number of subjects on the dependent variable

A. the effect of the independent variable on the dependent variable

In a one-way ANOVA, as the sum of squares within increases, the probability of accepting the null hypothesis

A. decreases

B. increases

C. remains constant

D. you cannot tell because the degrees of freedom within changes depending on the value of the sum of squares within.

b. increases

If the F statistic is significant in the 1-way ANOVA, the next step to take would be

A. to report the result and reject the null hypothesis.

B. to report the result and accept the null hypothesis

C. to accept the null hypothesis and conduct a post-hoc test

D. to reject the null hypothesis and conduct a post-hoc test

D. to reject the null hypothesis and conduct a post-hoc test

Why do we conduct a post-hoc test if we find a significant F in a one-way ANOVA?

A. Because the book and Prof. Kilianski told us to.

B. Because the sum of squares within underestimates the population sum of squares

C. Because you don't know which means differ from which other ones when there are more than two of them.

D. Because smaller sample sizes are less likely to yield significant differences, and each group is a smaller sample than the total N.

C. Because you don't know which means differ from which other ones when there are more than two of them.

Assuming that the mean differences and standard deviations are constant, you are less likely to reject the null hypothesis when using a paired-samples t-test than an independent samples t-test.

True

False

false

In a 1-way ANOVA, if the sum of squares between remains constant and the number of means being compared increases, you are more likely to find a significant difference among the means.

True

False

false

In a 1-way ANOVA, both the number of levels of the independent variable and the size of the sample influence the degrees of freedom within.

True

False

true

The reason there is only one number shown for degrees of freedom in any t-test is because the degrees of freedom between must always be 1.

True

False

true

For an independent samples t-test and a paired samples t-test with same number of subjects, the degrees of freedom would be the same.

True

False

false

With respect to a factorial ANOVA, if both main effects are significant, the interaction must also be significant.

True

False

false

In a factorial ANOVA, when neither main effect is significant, the interaction may still be significant.

True

False

true

When an ANOVA results in the rejection of the null hypothesis, the between-group variability must be greater than the within-group variability.

True

False

true

The effect size statistic for the 1-way ANOVA is

A. eta-squared

B. partial eta squared

C. Cohen's d

D. the coefficient of determination

a. eta-squared

The effect size statistic for the paired-samples t-test is

A. eta squared

B. partial eta squared

C. Cohen's d

D. the coefficient of determination

c. cohen's d

The coefficient of determination is equal to _______ and tells us ___________.

A. the SSbetween divided by the SS within, the effect size of F

B. the SS between divided by the SS between + SS within; the effect size of F

C. r squared; the % of variability in Y accounted for by X

D. sqrt of r; the % of variability in Y accounted for by X

C. r squared; the % of variability in Y accounted for by X

A study found that, compared to a placebo, a drug intended to reduce hyperactivity in teenagers reduced hyperactivity in those under 15, but increased hyperactivity in those under 15. This result would be described as

A. a main effect for age and a main effect for the drug

B. an interaction between the drug and hyperactivity

C. an interaction between age and hyperactivity

D. an interaction between the drug and age

D. an interaction between the drug and age

In #24 above, which F values would be most likely to be significant?

A. The F for the effect of age

B. The F for the effect of drug

C. The F for the interaction

D. It is most likely that all 3 F values are significant.

C. The F for the interaction

In the paired samples t-test, the value of t tells you how many _______ you are from ______________.

A. estimated std. errors of the mean ; the population mean

B. estimated std. errors of the mean ; 0

C. estimated std. errors of the difference; the population mean

D. estimated std. errors of the difference ; 0

D. estimated std. errors of the difference ; 0

With respect to the relationship between t and F, which of the following is true?

There is no relationship: they are two completely different inferential statistics

t is only for determining difference in sample means, F is for determining differences among population means

t = F(squared)

F = t(squared)

F = t(squared)