Question

The owners of an eyeglass store claim that they fill customers' orders, on average, in 60 minutes with a standard deviation of 15.9 minutes. Based on a random sample of 40 orders, a reporter determines a mean order time of 63 minutes. Let µ represent the average number of minutes to fill an order. What is the z-statistic?

Answer 1

the first answer is 1.19

the second answer is 1.65

Answer 2

We are given:

μ=60

σ=15.9

n=40

`\bar{x}=63`

`z=\frac{\bar{x}-\mu}{(\sigma)/(√(n))}`

`=(63-60)/((15.9)/(√(40)))`

`=(3)/(2.5140)`

`=1.19`

Therefore, the z-statistic is 1.19