# Thread: Hypothesis testing with no SAMPLE standard deviation?!

1. ## Hypothesis testing with no SAMPLE standard deviation?!

Hi, I was wondering if anyone could help me. Today I had my statistics final, and the last question on the test asked us to answer (in fifteen words or fewer) what to do if we had a hypothesis test for population mean for which we not only didn't know the population standard deviation, but also the sample standard deviation. Does anyone know how (or if) you can do anything?

2. I guess you have $\displaystyle \bar X$?

But if you have the data you can do a t test, but there you need to calculate $\displaystyle S^2$.

If you don't have normality you can do an approximate test via the central limit theorem if n is large.

If you don't have normality and n is small I guess you can do a nonparametric test.

You can do a lame approximation of S via range divided by four, but that is based on normality.

SO, I don't exactly know what your instructor is getting at.

3. Yeah, it said sample mean was given.

Thanks for your response. I just wanted to make sure I wasn't completely clueless about something...