Quiz (Chapter 15)

The Analysis of Covariance

  1. The analysis of covariance is often referred to by means of what abbreviation?
  3. The analysis of covariance can't be used in studies involving factors that are within-subjects in nature.
  4. True
  5. There ___ an ANCOVA counterpart to any ANOVA.
  6. is
The Three Different Variables Involved in Any ANCOVA Study
  1. ANCOVA studies contain at least one _____ variable in addition to the independent and dependent variables.
  2. active
  3. The variable identified in question 4 is more similar to the study's _____ variable.
  4. dependent
  5. The covariate variable is sometimes referred to as the _____ variable.
  6. concomitant
The Covariate's Role
  1. If a good covariate is used, the ANCOVA will have ___ power than will its ANOVA counterpart.
  2. more
  3. A good covariate functions to ____ the size of "error variance."
  4. increase
  5. While one function of the covariate is connected to "power," the other function is related to "_____."
  6. control
  7. In Excerpt 15.4, the "control" feature of the ANCOVA functioned to make the two sections comparable in terms of ________.
  8. absence frequency
  9. Will the group with the highest covariate mean have its mean on the dependent variable adjusted up or down?
  10. Up
  11. Researchers must choose to use a covariate either to increase power or to use it to exercise control; covariates can't be used to do both things at the same time.
  12. True
Null Hypotheses
  1. How many null hypotheses were associated with the ANCOVAs in Excerpts 15.1 and 15.2?
  2. 1; 1
    1; 2
    1; 3
    None of the above
  3. An ANCOVA null hypothesis always deals with adjusted ____ means on the ____ variable?
  4. sample; independent
    sample; dependent
    sample; covariate
    population; independent
    population; dependent
    population; covariate
The Focus, Number, and Quality of the Covariate Variable(s)
  1. In ANCOVA studies, the covariate variable ___ be different from the dependent variable.
  2. can
  3. Excerpt 15.5 is typical of ANCOVA studies in that only one covariate variable was involved (rather than multiple covariate variables).
  4. True
  5. The covariate variable ____ conceptually related to the dependent variable.
  6. should be
    need not be
Presentation of Results
  1. If a summary table is built to show the results of Excerpt 15.3's ANCOVA, it would contain __ F-values.
  2. 1
  3. In Excerpt 15.7, the 2nd df associated with the 3rd F-ratio is
  4. incorrect; it should be 56
    incorrect; it should be 57
    incorrect; it should be 58
  5. Suppose ANCOVA is used in a study on thin people to compare two different diets (A and B) on weight gain over a 4-week period. Suppose further that pre-diet weight is the covariate while post-diet weight is the dependent variable. Finally, suppose that the pre and post means (in pounds) for people in diet A are 140 and 160, respectively, while the pre and post means for people in diet B are 135 and 150. In this study, ANCOVA would cause diet A's adjusted mean to be ____ than its unadjusted mean.
  6. higher
  7. In Excerpt 15.13, the mean scores contained in the excerpt's middle sentence are _____ means.
  8. cell
    main effect
    both cell and main effect means
The Statistical Basis for ANCOVAšs Power Advantage and Adjustment Feature
  1. In ANCOVA studies, a covariate variable will do a better job of increasing power and providing control if it has a strong relationship with the _____ variable.
  2. independent
  3. In evaluating the relationship alluded to in Question 22, the researcher should focus on the pooled within-group correlation rather than the correlation based on all comparison groups thrown together.
  4. True
  5. When multiple covariate variables are involved in an ANCOVA study, those covariate variables work best if they have a _____ relationship with one another.
  6. strong
  1. The regular assumptions of ANOVA ___ apply to ANCOVA studies.
  2. do
  3. One unique-to-ANCOVA assumption says that the _____ variable should not affect the _____ variable.
  4. independent; dependent
    dependent; covariate
    independent; covariate
    covariate; independent
    covariate; dependent
  5. The assumption mentioned in Question 26 was ____ in Excerpt 15.12.
  6. met
  7. With equal sample sizes, ANCOVA is robust to the assumption of equal regression slopes.
  8. True
  9. If the sample sizes are equal, ANCOVA is robust to the assumption of linearity.
  10. True
  11. You are likely to come across ___ ANCOVA studies in which assumptions are not discussed.
  12. few
ANCOVA When Comparison Groups Are Not Formed Randomly
  1. Were "intact groups" used in the studies that supplied Excerpts 15.9 and 15.20?
  2. Intact groups were used in both studies.
    Intact groups were used in Excerpt 15.9's study but not Excerpt 15.20's study.
    Intact groups were used in Excerpt 15.20's study but not Excerpt 15.9's study
    Intact groups were not used in either study.
  3. When the population means on the covariate differ, ANCOVA's sample-based adjusted means on the dependent variable ____ be biased.
  4. will
  5. Simply on logical grounds, ANCOVA _____ be viewed as able to equate intact groups.
  6. should
Related Issues
  1. The Bonferroni adjustment technique ___ be used in ANCOVA studies.
  2. can
  3. In Excerpt 15.20, d was used as an estimate of effect size. Based on the criteria for evaluating this measure of practical significance, the final of the 3 findings would be labeled as being
  4. small
  5. With ANCOVA, only omnibus F-tests and post hoc comparisons are possible, not planned comparisons.
  6. True
A Few Warnings
  1. Your critique of an ANCOVA article should go ____ if it doesn't contain adjusted means.
  2. up
  3. In testing assumptions, researchers should use an alpha level that's more _____ than .05.
  4. "lenient"
  5. Which of these studies would yield results that are easier to interpret: (a) a one-way ANCOVA used with intact groups or (b) a one-way ANOVA used with randomly formed groups?
  6. Study a
    Study b


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