Final answer:
The standard deviation of the binomial distribution is 4.
Step-by-step explanation:
The standard deviation of a binomial distribution can be calculated using the formula:
sd = sqrt(np(1-p))
In this case, there are 100 students and the probability of a student planning to go to graduate school is 0.8. So the standard deviation is:
sd = sqrt(100*(0.8)*(1-0.8)) = sqrt(16) = 4
The correct answer is a. 4.