A multiple-choice test with 48 questions has four choices for each question.What is the probability of getting more than 12 questions correct by just guessing?
A)0.5000
B)0.4325
C)0.5675
D)0.0675

Question

A multiple-choice test with 48 questions has four choices for each question.What is the probability of getting more than 12 questions correct by just guessing?​
A)​0.5000
B)​0.4325
C)​0.5675
D)​0.0675

Quizplus · Accepted Answer

The probability of guessing any one question correctly is 1/4. The probability of guessing more than 12 questions correctly can be found by using the binomial probability formula: P(X > 12) = 1 - P(X ≤ 12), where X is the number of questions guessed correctly. Using a calculator or software, we can find:
P(X > 12) = 1 - binomcdf(48, 1/4, 12) = 0.4325
Therefore, the best choice is B: 0.4325.

A Multiple-Choice Test with 48 Questions Has Four Choices for Each