Exercise 1.

Ecology: WolvesThe following is based on information taken from The Wolf in the Southwest:

The Making of an Endangered Species, edited by David Brown (University of Arizona Press). Before 1918, approximately 55% of the wolves in the New Mexico and Arizona region were male, and 45% were female. However, cattle ranchers in this area have made a determined effort to exterminate wolves. From 1918 to the present, approximately 70% of wolves in the region are male, and 30% are female. Biologists suspect that male wolves are more likely than females to return to an area where the population has been greatly reduced.

(a)Before 1918, in a random sample of 12 wolves spotted in the region, what was the probability that 11 or more were male?

(b)Before 1918, in a random sample of 12 wolves spotted in the region, what was the probability fewer than 3 were female?

(c)For the period from 1918 to the present, what is the probability that at least 2 will be Male?