15.35 Do the calculations by hand. Exercise 15.34 gives data on the counts of insects attracted by boards of four different colors. Carry out the Kruskal-Wallis test by hand, following these steps.

(a) What are I, the ni, and N?

(b) Arrange the counts in order and assign ranks.

Be careful about ties. Find the sum of the ranks Ri for each color.

(c) Calculate the Kruskal-Wallis statistic H. How many degrees of freedom should you use for the chi-square approximation to its null distribution?

Use the chi-square table to give an approximate P-value.