A lot (collection) consisting of 200 fuses is inspected by taking 10 fuses at random and without replacement. If all 10 "blow" at the correct amperage, the lot is accepted. If there are 20 defective fuses in the lot and the random variable X equals the number of defectives among the 10 selected, find the p.m.f., the mean, and the variance of X. What is the probability of accepting the lot? Find the probability using the hypergeometric distribution, then the binomial approximation, and finally the Poisson approximation.