Question

A sample of 144 was taken from a population with a standard deviation of 36 inches. In this case, the sample mean will be within how many inches of the population mean 99.7% of the time?

A. 9
B. 6
C. 3
D. 12

Answer 1

@jim_thompson5910

Answer 2

I have this so far:

mean +/- z score * standard error
mean +/- z score * (standard deviation of population) / sqrt(n)
144 +/- 3* 36 / sqrt(144)

Answer 3

Would this be how you solve this?

3* 36 / sqrt(144) = 9

Answer 4

That looks correct

Answer 5

so 9 would be the answer?

Answer 6

yes

Answer 7

ok thanks :)