The lifetime of a car is assumed to be normally distributed with an average of 40 years and a standard deviation of 6.3 years. the probability that the lifetime of any given car is more than 32 years?

Answer 1

let x = years

P(x > 32)

x is N(40,6.3) (mean 40 standard deviation SD) = 6.3)

compute z-statistic = (x - mean)/SD for x = 32

z = (32-40)/6.3 = -1.27

P(x > 32) = P(z > -1.27) = 1 - P(z < -1.27) = 1 - 0.1020 = 0.898