Hi,

I need help with a function to determine POPULATION size based on a known sample size, confidence level and confidence interval.


I know my sample (s) is 314.
My confidence level is 95% (~ z-score of 1.96)
I want my confidence interval to be +/- 5% (0.05)


What population would this equate to and what is the formula to calculate this please?

I can work a z-score out from known pops/sample sizes, but am having problems re-arranging the formula to do this the other way around.

Thanks!