Question

You take a sample of 144 observations and have a value of x bar equal to 59. The population mean is 68 and the population standard deviation is 36. What is the z score of your sample mean?

Answer 1

`-3`

Explanation:

we use the standardising formula

`Z=(barX-mu)/(sigma/sqrtn)`

we have

`barX=59`

`mu=68`

`sigma=36`

`n=144`

`:.Z=(59-68)/((36/sqrt144))=-9/(36/12)`

`Z=-9/3=-3`