# ANCOVA

What is the purpose of including covariates in ANOVA?
To reduce within-group error variance
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What is another purpose of including covariates in ANOVA?
Elimination of confounds, once a possible confounding variable has bee identified it can be measured and entered into the analysis as a covariate
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What are the two additional considerations of an ANCOVA?
Independence of the covariate and treatment effect and homogeneity of regression slopes
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What is an independence of the covariate and treatment effect?
The covariate should not be different across the groups in the analysis (If you did an ANOVA or T-test using the groups as the independent variable and the covariate as the outcome, this analysis should be non sig.
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What is the homogeneity of the regression slopes?
Fit a regression line to the entire data set, ignoring to which group a person belongs. We should therefore assume that the overall relationship is true for all groups of participants.
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When are planned contrasts used?
generated specific hypotheses before the experiment use planned contrasts;
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When are post hocs used?
When there is not a generated hypothesis
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What is affected by including a Covariate?
The error mean square, between mean square and the f ratio
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## Other cards in this set

### Card 2

#### Front

What is another purpose of including covariates in ANOVA?

#### Back

Elimination of confounds, once a possible confounding variable has bee identified it can be measured and entered into the analysis as a covariate

### Card 3

#### Front

What are the two additional considerations of an ANCOVA?

### Card 4

#### Front

What is an independence of the covariate and treatment effect?

### Card 5

#### Front

What is the homogeneity of the regression slopes?