A psychologist would like to examine the effects of a new drug on the activity level of animals. Three samples of rats are selected with n = 5 in each sample. The rats in the first sample serve as a control and do not get any of the drug. The rats in the second group receive a small dose, and the rats in the third group each get a large dose of the drug. The psychologist records the activity level for each animal. The data from this experiment are presented below.

1. Do these data indicate any significant differences among the three groups? Test with ? = .05.

2. Compute ?2, the percentage of variance accounted for by the treatment.

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