An exam consists of ten true-or-false questions. If a student guesses at every answer, what is the probability that he or she will answer exactly seven questions correctly?
A) 0.105
B) 0.775
C) 0.805
D) 0.669
E) 0.117
F) 0.539

Question

Quizplus · Accepted Answer

The probability of guessing correctly on a true-or-false question is 0.5. The probability of getting exactly 7 correct answers out of 10 is given by the binomial probability formula: P(X = k) = C(n, k) * (p^k) * ((1-p)^(n-k)), where n = 10, k = 7, and p = 0.5. Calculating this gives approximately 0.117.

An Exam Consists of Ten True-Or-False Questions