QUESTION: A senior at a large university thinks he should invest more time into improving his resume due to the low amount of interviews he believes he is receiving. He claims that on average he receives approximately 10 hits per day from a job hunting site.
His statistics friends have been tracking their own hits on that same site for many months and feel that their true mean is 49 hits per day, so the null hypothesis would be
H0: μ = 49.
My question here is why is it 49? I thought the null hypothesis was when there is no difference than the original case. So then the original, no difference case would be H0: μ = 10? Right?
The problem also says that the alternative hypothesis is: Ha: μ < 49.
I don't know why. My answer would have be Ha: μ > 49.
I feel like I am missing something since there is a very specific number the questioner has in mind, 49, so then that changes the set-up of the null and alternative.
Will gladly up-vote best answer
Thank you
It's not clear as to what exactly you are testing. If you're testing whether you average less hits than your friends then your null hypothesis would be that you average the same amount of hits as your friends. Hence
$$H_0 : \mu=49$$
against the alternative that you average less than $49$ hits, hence
$$H_a : \mu < 49$$
As for testing whether there is a significant difference, we would need more information.