A simple random sample of n = 20 plots are selected for an aerial survey and the following numbers of moose are detected: 0, 0, 0, 0, 1, 2, 6, 11, 5, 1, 9, 3, 1, 0, 10, 4, 7, 22, 0, 0. Assuming detectability of 0.89, estimate the mean number of moose and give an estimate of variance. The study region contains N = 100 plots.