List the criteria for a binomial experiment. What does the random variable of a binominal experiment measure

List the criteria for a binomial experiment.  What does the random variable of a binominal experiment measure?

Consider a binomial experiment.  If the number of trials increased, what happens to the expected value? To the standard deviation?  Explain.

A stationery store has decided to accept a large shipment of ball-point pens if an inspection of 20 randomly selected pens yields no more than two defective pens.

a)      Find the probability that this shipment is accepted if 5% of the total shipment is defective.

b)      Find the probability that this shipment is not accepted if 15% of the total shipment is defective.