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Chapter 3: Measures of Variability
The formula says that you subtract the sample mean from each data value
and square the differences, you then add these values together, and divide
this sum by the sample size minus one.
Note:
Do not let the formula intimidate you. We will build a table to help with the
computations.
Example 3-8:
What is the variance for the following sample values?
3, 8, 6, 14, 0, 11
Solution:
First of all, we need to compute the sample mean. We can use
the
Basic Statistics
workbook to compute the sample mean.
Figure 3-13
shows the value to be equal to 7 when the values are entered in
the Data 1 column.
Figure 3-13:
Display with Sample Mean for
Example 3-8
Click here for the Basic Statistics Workbook