The main difference can be directly observed in the formulas used to calculate for the margin of error.
For the population mean, the margin of error would simply be:
MOE = z * s / sqrt(n)
where z is the z-score, s is the standard deviation and n is the number of samples
For the population proportion, the margin of error is:
MOE = z * sqrt[p (1 – p) / n]
where p is the probability of success