A university administrator expects that 25% of students in a core course will receive an A. He looks at the grades assigned to 60 students. The probability that the proportion of students that receive an A is 0.20 or less is ________.
A) 0.1855
B) 0.6266
C) 0.8133
D) 0.8900

Question

Quizplus · Accepted Answer

This is a binomial probability problem that can be approximated using the normal distribution because the sample size is large. The expected proportion of students receiving an A is 0.25. To find the probability of the proportion being 0.20 or less, we calculate the z-score for 0.20 and use the normal distribution to find the probability. The calculation yields a probability of approximately 0.1855, making option A correct.

A University Administrator Expects That 25% of Students in a Core