A normal population has mean and standard deviation . (a) What proportion of the population is greater than ? (b) What is the probability that a randomly chosen value will be less than .

Question

A normal population has mean 

=μ60

 and standard deviation =σ17

.(a) What proportion of the population is greater than 

96

?(b) What is the probability that a randomly chosen value will be less than 

81

.

Answer 1

z-statistic = (x - mean)/SD

here the mean s 60 and the standard deviation is 17

a) Compute z-statistic for x = 96.

Find P(z > z-statistic) from standard normal probability table

b) Compute z-statistic for x = 81

Find P(z < z-statistic) from standard normal probability table