The mean of a set of numbers is the sum divided by the number of terms.

Subtract from .

Subtract from .

Subtract from .

Cancel the common factor of and .

Factor out of .

Cancel the common factors.

Factor out of .

Cancel the common factor.

Rewrite the expression.

Move the negative in front of the fraction.

Divide.

Find the Mean (Arithmetic) {3,-6,-15,-24}