Statistically Confident
 

I am trying to creat a worksheet that will give me a number of random samples
I should take to be statistically confident that I can assign the results to
the remaining group. (ie. If I pull 15 samples out of a group of 50, and
all samples are favorable, I can be 95% confident that the remaining items
would have the same outcome).

Is there a way I can use excel to generate this?

Thank you.