Percent of Statistics?

A survey of college statistics professors showed an average salary of $42,000 per year with a standard deviation of $6,000. What percent of statistics professors earn between $36,000 and $48,000?





a. 85%


b. 95%


c. 68%


d. None of the above

Percent of Statistics?
It is c. 68% of statistical data lie within +/- 1 standard deviation of the mean.
Reply:This involves usage of The Empirical Rule.


You can draw out a graph of a bell-shaped distribution, in the middle place your standard deviation ($6,000)- to the left and to the right of that, equally spaced apart, draw a line on each side. Each of those lines are a standard deviation to the left and to the right. 42,000 - 6,000 is one standard deviation to the left. 42,000 + 6,000 is one standard deviation to the right.