hypothesis testing


New Member
I need help learning this. I know how to come up with the null and alternative statements but i don't know how to determine which one is the the original claim. I need to figure this out because my teacher wants us to write conclusion in a specific. So is there any way of determining this?

If you need to see a question, i'll post one.
1. You are the manager of a restaurant that delivers pizza to college dormitory rooms. You have just changed you delivery process in an effort to reduce the mean time between the order and completion of delivery from the current 25 minutes. From past experiences, you can assume that the population standard deviation is 6 minutes. A sample if 36 orders using the new delivery process yields a sample of 22.4 minutes.

a) Using 0.05 as the level of significance, is there evidence that the mean delivery time has been reduced below the previous population mean value of 25 minutes?
I know this:

H0: Mean >= 25
h1: Mean < 25

But which one is my original am i supposed to use what it says in a) if i do its not always the case because there are other questions where that one isnt. So how do i go about figuring which one is my original statement in this question or in any question.


there is not a general rule for determining of H0 or H1,
but it is usual that H0 is whatever have been before .