A Sample of Assistant Professors on the Business Faculty at State

Multiple Choice

A sample of assistant professors on the business faculty at state supported institutions in Ohio revealed the mean income to be $72,000 for 9 months with a standard deviation of $3,000. Using Chebyshev's Theorem, what proportion of the faculty earns more than $66,000 but less than $78,000?

A) At least 50%
B) At least 25%
C) At least 75%
D) At least 100%