Chapter Summary
A balanced experiment assigns an equal number of subjects to each treatment. Side-by-side boxplots are useful to visually compare the responses. Experimental data are often arranged in a tabular notation with subscripts to identify observations and categories. To judge the statistical significance of differences among the means of several groups, a one-way analysis of variance (ANOVA, or ANOVA regression) regresses the response on dummy variables that represent the treatment groups. The regression requires dummy variables for all but one group. The intercept in the regression is the mean of the baseline category, and each slope estimates the difference between the mean of a group and the mean of the baseline group. The analysis ...
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