A student takes a true-false test that has 12 questions and guesses randomly at each answer. Let X be the number of questions answered correctly. Find P(5)
A)0.1934
B)0.1208
C)0.0002
D)0.2256

Question

Quizplus · Accepted Answer

The probability of guessing exactly 5 questions correctly out of 12 in a true-false test (where each question has a 50% chance of being correct) can be calculated using the binomial probability formula: P(X=k) = (n choose k) * p^k * (1-p)^(n-k), where n=12, k=5, and p=0.5. This results in P(5) = (12 choose 5) * (0.5)^5 * (0.5)^(12-5) = 0.1934.

A Student Takes a True-False Test That Has 12 Questions