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

Simplify the numerator.

Add and .

Add and .

Add and .

Add and .

Divide.

Convert to a decimal value.

Convert to a decimal value.

Convert to a decimal value.

Convert to a decimal value.

The simplified values are .

Set up the formula for sample standard deviation. The standard deviation of a set of values is a measure of the spread of its values.

Set up the formula for standard deviation for this set of numbers.

Subtract from .

Raise to the power of .

Subtract from .

Raise to the power of .

Subtract from .

Raise to the power of .

Subtract from .

Raise to the power of .

Subtract from .

Raise to the power of .

Add and .

Add and .

Add and .

Add and .

Subtract from .

Divide by .

The standard deviation 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.

Find the Standard Deviation 3 5 7 9 9