(b) Using the second survey, calculate the estimated proportion using the equations for proportions in clusters, where clusters are not equal in size. Also calculate a 95% confidence interval for this estimate. Hint: Use the following formulas for (b): p= S. 1 y-2pym)+ p m (N- nm n-1 -n N where y. is the number of beetle-attacked trees in the ith plot and m, is the total number of trees in the ith plot.