Data Set 7-4: A set of scores with a mean of 16 and a standard deviation of 3.
-Look at Data Set 7-4. Suppose 200 persons received scores during a period of a week. How many would have scores of 15 or larger?
A) 15
B) 100
C) 45
D) none of the other alternatives are correct.

Question

Quizplus · Accepted Answer

Given the mean is 16 and the standard deviation is 3, a score of 15 is one-third of a standard deviation below the mean. In a normal distribution, about 50% of the values lie above the mean, and since 15 is very close to the mean, slightly more than 50% of the 200 persons would have scores of 15 or larger. None of the provided numerical options accurately reflect this, making D the correct choice.

Data Set 7-4: a Set of Scores with a Mean