Question

3) The mean height of men in the USA (ages 20-29) is 69.9 inches. A random sample of 60 men in this age group is selected. What is the probability that the mean height for the sample is less than 70 inches? 2 3

Answer 1

P( $\bar x$ < 70)

= P(( $\bar x$ - $\mu$ )/( $\sigma/\sqrt n$ ) < (70 - $\mu$ )/( $\sigma/\sqrt n$ ))

= P(Z < (70 - 69.9)/(3/ $\sqrt 60$ ))

= P(Z < 0.26)

= 0.6026