When circuit boards employed in the manufacture of MP3 players are tested, long-run percentage of defectives is 5%. Let X be the number of defectives in a random sample of size n=25, so X~Bin(25,.05).
a) Determine P(X <= 3).
b) Determine P(X >= 2).
c) Determine P(1 <= X <= 4).
d) Calculate E(X) and V(X).