,

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

To write as a fraction with a common denominator, multiply by .

To write as a fraction with a common denominator, multiply by .

Write each expression with a common denominator of , by multiplying each by an appropriate factor of .

Multiply and .

Multiply by .

Multiply and .

Multiply by .

Combine the numerators over the common denominator.

Simplify the numerator.

Multiply by .

Add and .

Multiply the numerator by the reciprocal of the denominator.

Multiply and .

Multiply by .

Divide.

The mean should be rounded to one more decimal place than the original data. If the original data were mixed, round to one decimal place more than the least precise.

Set up the formula for variance. The variance of a set of values is a measure of the spread of its values.

Set up the formula for variance for this set of numbers.

Simplify the numerator.

To write as a fraction with a common denominator, multiply by .

Combine and .

Combine the numerators over the common denominator.

Simplify the numerator.

Multiply by .

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.

Apply the product rule to .

One to any power is one.

Raise to the power of .

To write as a fraction with a common denominator, multiply by .

Combine and .

Combine the numerators over the common denominator.

Simplify the numerator.

Multiply by .

Subtract from .

Divide by .

Raise to the power of .

To write as a fraction with a common denominator, multiply by .

Combine and .

Combine the numerators over the common denominator.

Rewrite in a factored form.

Multiply by .

Add and .

Divide by .

Simplify the expression.

Subtract from .

Divide by .

Approximate the result.

Find the Variance 11/15 , 1/12