Question

Assume that the heights of men are normally distributed with a mean of 70.8 inches and a standard deviation of 4.5 inches. If 45 men are randomly​ selected, find the probability that they have a mean height greater than 72 inches.

​(Round

your answer to three decimal

places​.)

Answer 1

Solution :

Given that ,

mean = = 70.8

standard deviation = = 4.5

n = 45

= 70.8

= / n = 4.5 / 45 = 0.67

P( >72 ) = 1 - P( <72)

= 1 - P[( - ) / < (72-70.8) /0.67 ]

= 1 - P(z <1.79 )

Using z table

= 1 - 0.9633

= 0.0367