The weekly mean income of a group of executives is $1,000 and the standard deviation of this group is $100. The distribution is normal. What percent of the executives have an income of $925 or less?
A) About 15%
B) About 85%
C) About 50%
D) About 23%
E) None of the choices are correct

Question

Quizplus · Accepted Answer

The z-score for an income of $925 is (925 - 1000) / 100 = -0.75. The area to the left of a z-score of -0.75 is about 0.23, or 23%.

The Weekly Mean Income of a Group of Executives Is