Fig. 16. Finding P(x $ 31.2) When u = 33 and o = .7 by Using a Normal Table Normal curve with mean j = 33 and standard deviation or = .7 P(x $ 31.2) Miloago, * 31.2 33 Standard normal curve P(z s -2.57) - _0051 (with a = 0 and or = 1) 2 - 31.2 - 33 -2.57 ACTIVITY 1. Assume that the waiting time x for an elevator is uniformly distributed between zero and six minutes. a. Write the formula for the probability curve of x. b. Graph the probability curve of x. c. Find P(2 Sx $4). d. Find P({0 s x s 2) or {5 sx $6}). 2. Let x be a normally distributed random variable having mean u = 30 and standard deviation o = 5. Find the z value for each of the following observed values of x: a. x = 25 b. x = 15 C. X = 50