Question 1 (1 point)
1. It is possible to calculate a two-sample t test even if we do not know the two population means.
True
False
2. In a two-sample t test with sample sizes of 30 in each sample, there are 28 degrees of freedom
True
False
3. The hypothesis testing procedures for comparing means of INDEPENDENT samples would be appropriate for comparing
a. IQ scores of children attending a public elementary school as they progress from grade to grade.
b. husbands’ and wives’ attitudes toward higher education.
c. male and female problem-solving skills (number of moves toward the correct solution) on a spatial puzzle task.
d. software “usefulness” ratings by users who try both Software A and Software B.
4. The hypothesis testing procedure for comparing means of DEPENDENT samples would be appropriate for comparing
a. differences in the religious beliefs of best friends.
b. the distance that 12-year-olds versus 14-year-olds can kick a soccer ball.
c. final grades in a course taught by Professor Jones compared with final grades in a course taught by Professor Smith.
d. birthweights of babies born to drug-addicted mothers and birthweights of babies born to mothers who are not drug-addicted.
5. Suppose that a researcher decides that he MUST obtain a Type 1 error level of no more than 0.01 in order to reject the null hypothesis. After analyzing his data he finds that the results are significant at p = 0.05 but not at p = 0.01. If he is not able to change the maximum allowed Type 1 error level, then the researcher should
a. retain the null hypothesis because 0.05 is greater than 0.01.
b. retain the null hypothesis because 0.05 is merely sampling error.
c. reject the null hypothesis because 0.05 is close to 0.01.
d. reject the null hypothesis because 0.05 is greater than 0.01.
6. “Children whose parents smoke in their presence are more likely to develop asthma than children whose parents do not smoke in their presence.” How many tails should be used when looking up the t test statistic for this study?
a. one tail
b. two tails
c. Either one tail or two tails – it doesn’t matter
d. there is not enough information to tell.
7. When subjects who are treated in the SAME way differ in performance, what accounts for their measured difference?
a. Between-groups variation
b. within-groups variation
c. total variation
d. treatment variation
8. “One way” means that
a. there is only one correct way to calculate the test statistic.
b. the results can be in only one direction.
c. there is only one sample (group) in the study.
d. there is only one IV in the study.
9. The appropriate statistic to use when testing the hypothesis for a study with three treatment groups is a
a. one-sample t test
b. two-sample t test
c. ANOVA F test
d. either B or C is appropriate
10. When and why would you conduct post-hoc tests as a follow up to the overall F test?
a. When the overall F test is NOT significant; to determine which of the pairs of groups may be significant.
b. When the overall F test is NOT significant; to determine why the overall F test is not significant.
c. When the overall F test is significant; to determine between which pairs of groups the significant difference lies.
d. When the overall F test IS significant; to determine if the significance is only the result of chance.
11. After the F tests indicate that there is statistical significance, a post hoc test indicates the _______ of that statistical significance.
a. size
b. direction
c. strength
d. location
12. You read that a study was conducted as a 3 x2 ANOVA. This study had how many independent variables?
a. 1
b. 2
c. 5
d. 6
13. A study has three treatment conditions for a single IV. What is the appropriate analytic technique?
a. one-sample t test
b. two-sample t test
c. one-way ANOVA
d. factorial ANOVA
14. A chi-square test is the appropriate analytic technique to use whenever the measurement scale for the data is
a. nominal
b. ordinal
c. interval
d. ratio
15. A t test always compares __________, while a x2 test always compares __________.
a. scores; ranks
b. scores; frequencies
c. expectations; observations
d. two groups; three or more groups
16. The effect size of a study helps determine if the statistical significance is a genuine treatment effect or merely an effect due to
a. random error
b. sample size
c. experimenter error
d. the IV.
17. Measure of effect size were created to guard against the impact of ___________ on statistical significance.
a. unscrupulous researchers
b. random error
c. normally distributed data
d. sample size
18. Power is
a. the ability to detect a true null hypothesis.
b. the ability to detect a false null hypothesis.
c. the same as Type 1 error.
d. the same as Type 2 error.
