Twenty third graders were randomly separated into four equal groups, and each group was taught a mathematical concept using a different teaching method. At the end of the teaching period, progress was measured by a unit test. The scores are shown below (one child in group 3 was absent on the day that the test was administered).

a. What type of design has been used in this experiment?
b. Construct an ANOVA table for the experiment.
c. Do the data present sufficient evidence to indicate a difference in the average scores for the four teaching methods? Test using a = .05.

Group 112 140 101 92 129 121 116 124 102 130 105 89 136 106 126 119 97 99