Confidence Interval for the proportion μ
Developed for small samples sizes, it is always safe to use the t distribution). WiP Developed for small samples sizes, it is always safe to use the t distribution). WiP 
The critical value of t can be found in Table A-3 by looking in the column for the area (significance level) in two tails and the row for the number of degrees of freedom. df = n - 1 
and the standard deviation, s of the sample if they are not given in the problem.