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

2 Answers
Dec 11, 2017

970.2

Explanation:

enter image source here

Dec 11, 2017

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