posted by apryl .
Suppose that people's heights (in centimeters) are normally distributed, with a mean of 175 and a standard deviation of 6. We find the heights of 40 people.
(a) How many would you expect to be between 169 and 181 cm tall?
(b) How many would you expect to be taller than 170 cm?
I don't know how you got your answers, but you answer needs to be less than 40.
Z = (score-mean)/SD
Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportions for the Z scores. Multiply the proportions by 40.
a = proportions between the two Z scores and mean.
b = proportion in the larger portion.