12.10 Determining the critical value of F. For each of the following situations, state how large the F statistic needs to be for rejection of the null hypothesis at the 0.05 level.

  1. (a) Compare three groups with four observations per group.

  2. (b) Compare three groups with five observations per group.

  3. (c) Compare four groups with five observations per group.

  4. (d) Summarize what you have learned about F distributions from this exercise.