On a multiple choice test with 27 questions, each question has four possible answers, one of which is correct. For students who guess at all answers, find the variance for the number of correct answers.
A) 25.6
B) 2.3
C) 50.6
D) 5.1

Question

Quizplus · Accepted Answer

The variance for a binomial distribution is calculated using the formula np(1-p), where n is the number of trials (questions) and p is the probability of success (correct answer). Here, n = 27 and p = 1/4. So, variance = 27 * (1/4) * (3/4) = 5.0625, which is approximately 5.1.

On a Multiple Choice Test with 27 Questions, Each Question