Step-by-step explanation:
Due to the time it took to solve this question, I had little time to type the answers fully
The answers are contained fully in the attachment I have uploaded.
A. H0: u1 = u2
H1: u1 not equal to u2
The t statistics was solved to be 3.03
The degree of freedom was solved to be 26
Given this information, this is a 3 tailed test, critical value at 5% = +-2.056
T stat > critical value
We therefore reject the null hypothesis at 5% and conclude they have different mean wear
The p value is calculated using excel and the result is 0.00544
We reject null at 5% since p value is less than 0.05
B. H0: u1 = u2
H1: u1>u2
Alpha = 0.05
Following a,
Test stat = 3.03
Df = 26
Critical value for 1 tailed test = 1.706
Test stat > 1.706
We reject H0 and conclude company 1 has higher mean wear.
We find p value for a right tailed distribution using excel
Tdist(3.03,26,1)
= 0.002722
We reject h0
C. Confidence interval
1.610 < u < 8.390
