An instructor has given his final exam,and scores are approximately normally distributed.Nancy scores a 90 and Ronald scores a 75.The characteristics of the distribution are as follows:
= 85,
S² = 36.What is Nancy's approximate percentile rank?

Question

Quizplus · Accepted Answer

Nancy's score is 90, which is 5 points above the mean (85). The standard deviation is the square root of the variance, which is 6. A score of 90 is (90-85)/6 = 0.83 standard deviations above the mean. Using a standard normal distribution table, a z-score of 0.83 corresponds to approximately the 80th percentile.

An Instructor Has Given His Final Exam,and Scores Are Approximately