Question

The average assembly time for a Ford Taurus is μ = 38 hrs. An engineer suggests that using a new adhesive to attach moldings will speed up the assembly process. The new adhesive was used for one month. During that month, the average assembly time for 36 cars was = 37.5 hours with a standard deviation s = 1.2 hours. Use α = 0.01. Based on the calculated P-value will you reject or fail to reject the null hypothesis? Select one: a. reject the null hypothesis / data is significant b. fail to reject the null hypothesis c. cannot be determined

Answer 1

a) reject null hypothesis since p < 0.01

Explanation:

Given that the average assembly time for a Ford Taurus is

`μ = 38 hrs`

Sample size
`n=36`

`x bar = 37.5\\s=1.2\\SE = 1.2/6 = 0.2`

Test statistic t = mean diff/se = 0.5/0.2 = 2.5

(Here population std dev not known hence t test is used)

df = 35

p value = 0.008703

a) reject null hypothesis since p < 0.01