1) We receive the shipment of 200 units, of which 18 are defective. We test ten units at random, and we model the number k of the units that test defective through a random variable x.
a) Find out the distribution of x
b) Find out P(x =2)
2) A machine makes fuses with the average of 1% defective. If random variable x shows the number of defective fuses in sample of 4, find out the probability density function as well as the distribution function of the random variable x.