A refrigerator manfacturer claims that the mean life of its

A refrigerator manfacturer claims that the mean life of its competitor\'s refrigerators is less than 14 years. You are asked to perform a hypothesis test to test this claim.

a) How would you write the null and alternative hypothesis if you represent the manfacturer and want to support the claim?

Ho: u,p,²,or

Ha: u,p, ²,

b) How would you write the null and alternative hypothesis if you represent the competitor and want to reject the claim?

Ho: u, p, ²,

Ha: u,p,²,

Solution

You usually write the claim you want on the alternative hypothesis.

Thus:

A.

You want to claim that the refrigerators\' life is less than 14. Thus, you put that as Ha:

Ho: u >= 14
Ha: u < 14

B.

This time, you want to claim that the refrigerators\' life is not less than 14. Thus, you put that as Ha:

Ho: u < 14
Ha: u >= 14