Question: Circuit boards used in the manufacture of compact disc players are tested, the long run percentage of defectives is 5%. Let X=the number of defective boards in a random sample size of n=25. (5 points)

a. Calculate the expected value of X. (1)

b. Calculate the variance of X. (1)

c. What is the probability that none of the 25 boards are defective? (1)

d. What is the probability that the number of defective boards is greater than 5? (2)