Thread: Hypothesis test

Hey I'm learning about Hypothesis test this week and the way my teacher explained it was very confusing. So I was wondering if i post a question and the answer I get could someone tell me if I did it right or not. Thank You.

For this problem I need to write its complement and which is Ho and Ha. the problem is u<128

I got Ha= u<128 and Ho= u > 128.

For this problem I need to determine wither the hypothesis test is tailed to the left, right or both. the problem is-The mean life of a certain tire is no less than 50,000 miles.

My answer is u > 50,000 and is tailed to the left.

The problem for this one is- A taxicab comp. claims that the mean travel time between 2 destinations is about 21 min. You work for a bus comp. and you reject this claim. How would you write the null and alternative hypthesis?

My answer is Ho= u> 21 min. and Ha= u>21 min

Thank you to whom responds I'm not sure if I'm doing this write.

(i) H0: u>=128
H1: u<128
this is left tail test.

(ii) H0: u>=50,000
H1: u<50,000
this is also left tail test.

(iii) H0:u<=21
H1:u>21
this is right tail test.