1) Analysis of variance should only be conducted when a. sample sizes are greate
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Question
1) Analysis of variance should only be conducted whena. sample sizes are greater than 30 per group.
b. there are less than 30 subjects per group.
c. population variances are equal.
d. population sizes are equal.
2) When an analysis of variance is conducted,
a. fewer subjects are required than when a t test for independent means is conducted.
b. two estimates of the population variance are compared.
c. difference scores are computed, as in a t test for dependent means.
d. all of the above.
3)In an analysis of variance, if the null hypothesis is true, then
a. the research hypothesis is also true.
b. fewer subjects are needed for the experiment.
c. there should be less variance among means of samples than if the null hypothesis were not true.
d. the within-group estimate of the population variance is smaller than the between-group estimate.
4) When conducting an analysis of variance, if the within-group variance estimate is about the same as the between-group variance estimate, then
a. the null hypothesis should be rejected.
b. any difference between sample means is probably due to random sampling error.
c. an error in the calculations was made, because within-group variance estimate must always be smaller than the between-group variance estimate.
d. any difference between sample means is probably due to a real difference caused by experimental conditions.
5) When conducting an analysis of variance, the null hypothesis is rejected when
a. the t score is significantly larger than the cutoff t.
b. the F ratio is significantly larger than 1.
c. the t score is significantly smaller than the F ratio.
d. the F ratio is significantly smaller than the t score.
6) In an analysis of variance, the population variance can be estimated within any one group by
a. finding the sum of squared deviations of the scores in that group from that group's mean, and then dividing that sum by that group's degrees of freedom.
b. finding the sum of squared deviations of the scores in that group from that group's mean, and then dividing that sum by the numerator degrees of freedom.
c. finding the sum of squared deviations of the scores in that group from the overall mean of all the scores (in all groups), and dividing that sum by that group's degrees of freedom.
d. finding the sum of squared deviations of the scores in that group from the overall mean of all the scores (in all groups), and dividing that sum by the numerator degrees of freedom.
7) When sample sizes are equal, S2Within, is calculated by
a. summing the population variance estimates computed within each group, and dividing by the total number of subjects.
b. summing the population variance estimates computed within each group, and dividing by the number of groups.
c. multiplying the within-group sum of squares (SSW) by the size of each sample (n).
d. dividing the within-group sum of squares (SSW) by the size of each sample (n).
10) For an analysis of variance, if the between-group estimate of the population variance is 30 and the within-group estimate is 25, then the F ratio is
a. 25/(30-25) = 5.00.
b. 30-25)/30 = 0.17.
c. 25/30 = .83.
d. 30/25 = 1.20.
11) If the within-group variance estimate is 8.5 and the between-group variance estimate is 5.3, what is the F?
a. 5.3/8.5= 0.62
b. 8.5/5.3= 1.60
c. /8.5= 0.27
d. /5.3=0.55
12) A study has three groups, each with an equal number of cases. The population variance is estimated from the variance within each group, yielding three estimates, 54.4, 48.6, and 50.9. What is the within-group estimate of the population variance?
a. (54.4+48.6+50.9)/(3-1) = 76.95
b. (54.4+48.6+50.9)/3 = 51.3
c. (54.4+48.6+50.9)/(3+1) = 38.48
d. (54.4+48.6+50.9)/(3+2) = 30.78
13) One characteristic of an F ratio is that
a. when looking up the cutoff F on a table, the degrees of freedom are needed from
numerator, denominator, and the sum of squares calculation.
b. it is never less than 0.
c. it is negatively skewed (the long tail to the left).
d. the standard t distribution (for 30 df) is used as a comparison distribution.
14) A two-way factorial design
a. is "two-way" because the influence of two separate variables is being studied.
b. varies only in name from a one-way analysis of variance.
c. considers two levels of a single variable.
d. considers a single level of two variables.
15) In research articles, the reporting of the results of a factorial analysis of variance
a. rarely includes a textual description.
b. are often shown in table format only.
c. are usually presented with a combination of table and textual description.
d. typically give brief explanations of the underlying logic of the factorial analysis of variance.
Explanation / Answer
1) Analysis of variance should only be conducted when the population sizes are equal.So, d is the correct one.
2) When an Anova is conducted, then the two estimates of the population variance are compared. 3) The within group estimate of the population variance is smaller than the between group estimate d is the correct anwer. 4) Any difference between sample means is probably due to random sampling error, so b is the correct answer. 5) b) The F-ratio should significantly larger than 1. 6) a is the correct one. Finding the sum of squared deviations of the scores in that group from that group's mean and then dividing that sum by that group's degrees of freedom.
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