Question

The population standard deviation for the height of high school basketball players is 2.5 inches. If we want to be 95% confident that the sample mean height is within 0.4 inch of the true population mean height, how many randomly selected students must be surveyed?

Fill in the blank: n=

Answer 1

= 2.5 (population standard deviation)

Margin of error(MOE) = 0.4

For 95% confidence interval the level of significance () = 0.05

So, the critical value = = = = +/-1.960

Let n be the required sample size

To get the value of n we solve the following equation:-

we know,  

sample size can not be in decimal so round to nearest whole number therefore, n is 150

Answer:

150 randomly selected students must be surveyed

n = 150