Question

A pizza delivery chain advertises that it will deliver your pizza 25 minutes from when the order is placed. A random sample of 13 customers recorded the time it took for their pizzas to be delivered and found that the mean time was 27.2 minutes, with a standard deviation of 4.3 minutes. Assume the population of delivery times is normally distributed and test the claim that the mean pizza delivery time is 25 minutes using a 5% level of significance.

a: state hypotheses

b: verify conditions that hold

c: calculate test statistic

d: calculate the p value

Answer 1

Solution :

= 25

=27.2

S =4.3

n = 13

This is the two tailed test .

The null and alternative hypothesis is ,

H₀ :    = 25

H_a :     25

Test statistic = t

= ( - ) / S / n

= (27.2-25) / 4.3 / 13

= 1.845

Test statistic = t = 1.845

P-value = 0.0899

= 0.05  

P-value >

0.0899 > 0.05

Fail to reject the null hypothesis .

There is not sufficient evidence to claim that the population mean μ is different than 25, at the 0.05 significance level.