1. In order to eliminate age as an explanation for a .55 correlation between oral vocabulary and reading proficiency, a researcher must determine:
A) the age of each subject
B) the correlation between age and oral vocabulary
C) the correlation between age and reading proficiency
D) all of the above
2. The rationale on which partial correlation is based includes:
A) determining the correlation between each original variable and the extraneous variable
B) adjusting each original variable by using its correlation with the extraneous variable
C) determining the correlation between the adjusted scores of each subject
D) all of the above
3. What do multiple regression, path analysis, and factor analysis all have in common?
A) They all result in a prediction equation.
B) They all are techniques for controlling threats to internal validity.
C) They all use the same basic equation.
4. In order to be a threat to the internal validity of an experimental study, an extraneous variable such as age must:
A) be related to the dependent variable
B) differ among treatment groups
C) both A and B
D) neither A nor B
5. Which of the following inference tests is not appropriate for a comparison of two means in a causal comparative study?
A) The Mann-Whitney U test -x
B) ANOVA -x
C) Chi-Square -O
D) A t test for independent means
6. The importance of a 15-point difference in means between two groups:
A) depends on the spread of scores in each group
B) depends on the shape of the frequency polygons
C) depends on the number of cases in each group
D) all of the above
7. In a comparison group study using two randomly selected groups, effect size=.24, and p<.01. This means the:
A) difference in means is small and probably due to sampling error
B) difference in means is small but probably is not due to sampling error
C) difference in means is large enough to be important, but may well be due to sampling error
D) difference in means is large and probably not due to sampling error