Activity 4 - Show your solution and explanation clearly.

1. Let X be a normally distributed random variable with = 21 and = 3. Find the value of k such that

(a) P(X k) = 0.2101

(b) P(X > k) = 0.9593

(c) P(X k) = 0.06

(d) P (X < 18) = P (Z < k)