1. By definition, IQ scores follow a normal distribution. Suppose that a specific IQ test is

devised to have a mean of 100 and a standard deviation of 20. Randomly select 25 adults.

(a) Determine P(X₁ > 105).

(b) Determine P(X > 105).

(c) Compute P(98 < X < 104).

(d) Determine P(X < 100).

(e) Find P(S2>240).

(f) Compute P(S ≤ 18).