In a True-False exam with 100 questions,passing requires a score of at least 60.What is the approximate normal probability that a "guesser" will score at least 60 points?
A)0.0287
B)0.4713
C)0.0251
D)0.0377

Question

Quizplus · Accepted Answer

The mean of the binomial distribution is np = 100 * 0.5 = 50, and the standard deviation is sqrt(np(1-p)) = sqrt(50 * 0.5 * 0.5) = 5. The probability of scoring at least 60 points is the area under the normal curve to the right of z = (60 - 50) / 5 = 2. The area to the right of z = 2 is approximately 0.0287.

In a True-False Exam with 100 Questions,passing Requires a Score