Refer to Exercise 15.14.
a. Use the Friedman test to determine if there is significant evidence of a difference in the mean number of counts for the six potential treatments for removing ice and snow from the roadway.
b. Compare the conclusions obtained from the Friedman test to the conclusions obtained from the AOV F test.
In exercise

Sodium Chloride Calcium Chloride Sand Roadway Lo High Low High Low High 37 43 42 47 45 56 47 48 50 54 63 27 27 36 50 31 37 37 48 57 45