A researcher wanted to see how watching movies influenced subjects' IQ scores. She gave IQ tests to subjects following each of two movies. Half of the subjects first saw Titanic followed by Schindler's List, while the other half first saw Schindler's List and then Titanic. Varying the movie order is an example of
a. counterbalancing.
b. random sampling.
c. selection bias.
d. practice effects.
Question 2
In a learning study using repeated measures, the correlation between early and later times will likely be low. Analyzing fewer levels of the independent variable would help to avoid violating the assumption of
a. normality.
b. homogeneity of variance.
c. constant correlations among pairs of levels of the repeated variables.
d. MSerror is an unbiased estimate of the magnitude of effect of the predictor variable in a regression analysis.