Question 3
Suppose X N(20,5)
(a) Find:
(i) P(X> 18) (5 marks)
(ii) P(7 < X < 15) (5 marks)
(b) Find the value a such that P(20-a < X < 20+ a) = 0.99 (10 marks)
(c) Find the value b such that P(20-b< X < 20+ b) = 0.95 (10 marks)