Question

Pizza delivery times at Pizza Time are normally distributed with a mean time of 27 minutes and a standard deviation of 3 minutes. Approximately what percent of pizzas are delivered between 24 and 30 minutes?

Answer 1

68% of the data will be within one standard deviation of the mean, so 68% of delivery times will be at least 27-3=24 and at most 27+3=30.

Answer 2

Answer: There is 34.13% of pizzas are delivered between 24 and 30 minutes.

Explanation:

Since we have given that

Mean time = 27 minutes

Standard deviation = 3 minutes

We need to find the percentage of pizzas are delivered between 24 and 30 minutes.

Since it is normally distributed.

So, it becomes,

`P(24<X<30)`

As we know that
`Z=(X-\mu)/(\sigma)`

so, we will substitute it :

`P((24-27)/(3)<(X-\mu)/(\sigma)<(30-27)/(3))\\\\=P(-1<Z<1)\\\\=2* P(0<Z<1)=0.34134\\\\=0.34134* 100=34.134\%`

Hence, there is 34.13% of pizzas are delivered between 24 and 30 minutes.