Assume that the distribution of weights of adult males is ap

Assume that the distribution of weights of adult males is approximately normally distributed with the mean of 179.8 lb and standard deviation of 93.0 lb.

Find the probability that a randomly selected male has a weight below 155.5 lb.

Solution

So the probability that a randomly selected male has a weight below 155.5 lb is

P(X<155.5) = P((X-mean)/s <(155.5-179.8)/93)

=P(Z<-0.26) = 0.3974 (from standard normal table)