A calculus student takes a 20-question, multiple choice test with 5 answer choices for each question. find the mean and standard deviation of the number of questions that he/she gets correct

Suppose the student guesses the answers, we shall consider this a binomial probability problem of success. This implies that getting a question right is p=1/5.

The number of questions is n=20 questions.

The mean of binomial distribution is

mean=n*p = 20*1/5=4

b] The standard deviation of a binomial distribution is given by:

σ=√ (n*p * (1-p))

=√ (20*0.2*0.8)

=1.79~1.8

Answer:

μ=4; σ=1.8