Eighty wheat plants were grown in each of five different fields. Each of six individuals (A, B, C, D, E, and F) were asked to pick eight "representative" plants in each field and measure the plants's heights. Measurements were taken on six different days. The data consist of the differences between the mean height of the eight "representative"

plants and the mean of all the heights in the field on that day. Thus the data measure the bias in selecting "representative" plants. The exact design and the data are given below. Analyze the data. (Although they are barely recognizable as such, these data are from Cochran and Cox, 1957.)

Field Day 1 2 3 4 5 1 E 3.50 A 0.75 C 2.28 F 1.77 D 2.28 2 D 3.78 B 1.46 A-1.06 E 1.46 F 2.76 3 F 2.32 C 2.99 B-0.28 D 1.18 E 3.39 4 C 4.13 D 4.02 E 1.81 B 1.46 A 1.50 5 A 1.38 E 1.65 F 2.64 C 2.60 B 1.50 6 B 1.22 F 2.83 D 1.57 A-1.30 C 1.97