# Sampling (Quant)

The mean population is 12 and Standard deviation is 3. Given population comprises 64 observations, what is the standard of error of sample mean? For the denominator n in the formula, do you use 64 or 12 and why ? Appreciated thank you.

You ask about the standard error of the sample mean without mentioning a sample.

Is there a sample? How big is it?

I am unsure but I got the question from IFT, hope it helps. In my opinion it should be 3 / Square root 12 instead ? Please let me know of your opinion thank you !

The formula given for the standard error in the answer is correct. However, n is the sample size (not the mean; never the mean), not the population size. They didn’t give you a sample size, so you cannot answer the question.

Also:

This makes no sense grammatically. The population is composed of 64 observations, or the population comprises 64 observations.

It’s a very poorly written question.

I see, so n= sample size, I think the question just looks confusing and not clearly stated. Anyway, Thank you so much for helping !