It depends upon the confidence level (99%, 95%, etc) of the sample. In this case, the population size is 100, and the sample size is 78. If it's in a 99% confidence level, margin of error is 7 (So between 71 - 85 undergrads). If it's in a 95% confidence level, the margin of error is 6 (So between 72 - 84 undergrads).
