Question

How do you find the sample variance in 89, 57, 104, 73, 26, 121, 81?

Answer 1

`970.2`

Explanation:

Answer 2

Use the formula for Variance of a Sample (not a Population).
`s^2 = (1/(N - 1))sum_(i=1)^N(x_i - barx)^2`

Explanation:

Many calculators, spreadsheets and even on-line calculators are available. It IS prudent to understand how to calculate it manually in every case! The formula for Variance of a Sample is:

`s^2 = (1/(N - 1))sum_(i=1)^N(x_i - barx)^2`

The Mean (`barx`) is `78.71`. The sum of the difference between it and the data values is divided by 1 less than the number of data for a sample.

In this case it is `970.2` Its square root is the Standard Deviation, which is `31.1`.

https://www.rapidtables.com/calc/math/variance-calculator.html