Refer to Exercise 15.16.
a. Use the Friedman test to determine if there is significant evidence of a difference in the mean yields for the 12 combinations of variety€“ planting density.
b. Compare the conclusions obtained from the Friedman test to the conclusions obtained from the AOV F test.
In exercise

Variety Sunbeam Celebrity Trust Density Density Density 20k 35k Field 5k 50k 5k 20k 35k 50k 5k 20k 35k 50k 32.5 39.9 42.5 38,2 33.4 47.2 44.5 43.5 411 48.7 53.5 48.4 32.2 43.2 47.6 43.5 33.4 51.3 52.244.1 418 512 55.955.9 49.9 59,0 66.3 58.3 60.8 66 70.7 60.6 60.8 67.6 73.2 67.8