# The choice of the method

#### Ming

##### New Member
Hi,

Just would like to ask for some of your valuable advice!

I am working on the project which would like to use the small sample to estimate the mean of the population.

The question is, in my situation, my sample size is quite large saying over 1000, should I change the formula for population instead of for sample in my case?

My problem is, when I divided the population standard deviation by the square root of sample size, the z very becomes very small and it make the p value comes to be zero but I know it is wrong.

Thanks for your sharing first