Question

Pete's Pizza has a mean delivery time of 29 minutes with a standard deviation of 3 minutes. Determine the z-score for the number of pizzas delivered in less than 25 minutes.

−1.33
1.33
8.33
9.67

Answer 1

-1.33

Explanation:

Answer 2

Answer: First Option

`Z<-1.33`

Explanation:

We know that the mean is:

`\mu=29\ minutes`

We know that the standard deviation is:

`\sigma=3\ minutes`

The formula to calculate the Z-scores is:

`Z=(X-\mu)/(\sigma)`

Where in this case
`X=25\ minutes`

Then the z-score for
`X=25\ minutes` is:

`Z=(25-29)/(3)`

`Z=-(4)/(3)`

The negative number means that the deviation is to the left of the mean. In other words 25minutes is at 1.33 standard deviations to the left of the mean

`Z<-1.33`