Formula for the Confidence interval?

Formula for the Confidence interval, assuming for a Sample whose standard deviation is same as Population.

I need to know the exact formula. I need to know if there is any square root of n in the denominator. Anyone who knows the formula please share.


TS Contributor
This is the interval 95% of the individual values will be contained in. To me it is a bit strange to call it a "confidence interval". The square n would come into the formula if you wanted to calculate the confidence interval of the population mean.