When circuit boards used in the manufacture of compact disc players arc tested, the long-run percentage of defectives is 5%. Let X= the number of defective boards in a random sample of size n=25, so

X∼Bin(25,0.05).


(a) Determine P(X=3).

(b) Determine P(X≤3).

(c) Determine P(X≥4).

(d) Determine P(1≤X≤3).

(e) What is the probability that none of the 25 boards is defective?