Question

Domino’s Pizza in Big Rapids, Michigan, advertises that they will deliver your pizza in less than 15 minutes of placing an order or it is free. A sample of 25 customers is selected at random. The average delivery time in the sample was 14 minutes with a sample standard deviation of 4 minutes. Test to determine if we can infer at the 5% significance level that the Domino’s claim is correct.

Answer 1

his is the left tailed test .

The null and alternative hypothesis is

H₀ : = 15

H_a : < 15

Test statistic = t

= ( - ) / s / n

= (14 - 15) / 4 / 25

= -1.25

Test statistic = -1.25

df = 24

P-value = 0.1117

= 0.05

P-value >

Fail to reject the null hypothesis .

Domino’s claim is not correct.