Hyp Testing?

Question

I have a hypothesis testing question which I'm having trouble with, any informative help would be welcome.

There is a hypothetical brewery and it has 5 taps for filling cans (which tap fills a can is entirely random). The can must be filled with 1000units, but above this has to be kept to a minimum to avoid overfilling. Every now and then a red can is sent through the system of blue cans, and the tap used to fill it and how much it is filled with is noted. Therefore I have a set of data with 30 fill amounts for each of the 5 taps.

By analysing the data decide if any tap appears to be filling the cans with more beer than other taps?

For this I have done hypothesis of; H0: u1-u2>=0 and HA: u1-u2<0. Is this correct?

If so, do I use the left tail of a one tailed distribtuion diagram?

Answer 1

You haven't said which is u1 and which is u2. It does appear to be a one sided test. If u2 is the mean for the test sample and u1 is 1000 units, then it appears that your test is correct and you should use just the left tail because you're looking at the possiblity of an overfill.