13.7 Describing a two-way ANOVA model. A 3 × 3 ANOVA was run with four observations per cell.

  1. (a) Give the degrees of freedom for the F statistic that is used to test for interaction in this analysis and the entries from Table E that correspond to this distribution.

  2. (b) Sketch a picture of this distribution with the information from the table included.

  3. (c) The calculated value of this F statistic is 3.03. Report the P-value and state your conclusion.

  4. (d) Based on your answer to part (c), would you expect an interaction plot to have mean profiles that look parallel? Explain your answer.