Hey everyone! I'm having difficulty figuring out this question. It seems simple and straightforward enough, but I need some guidance as to what I need to do.

I know the x̄=51.25 and s = 4.367 and n = 8 but I don't understand how to find the confidence interval from this point on..Consider the sample 49 53 49 47 52 61 50 49 from a normal population with population mean μ and population variance σ^{2}. Find the 95% confidence interval for μ

The formula I'm given is:

x̄ ± z_{a/2}* (s/√n)

I know x̄ and s are, and I know a/2 = 0.05/2, the z-score that lines up with (0.5-[0.05/2]) is 1.96, but I don't know n, so how would I solve this?

any help appreciated!

EDIT: I also know that x̄ is representative of μ.

The answer key says the answer is 51.25 ± 3.65, but I don't understand where 3.65 came from.