one tailed test or two test?
The question is "Some guy on the internet designed a weight-loss program. You are wondering if it is working. You are given a sample of some people who did the program"
according to the solution given, this is a one tailed test. but my question is this: why isn't it a two tailed test
we can have a null hypothesis as
H0 : The weight loss program IS working h1: the weight loss program IS NOT working
wont that be correct? and if so, then this makes it a two tailed test