What is the variance of {-13, 10, 8, -3, 6, 12, 7}?
1 Answer
Dec 18, 2015
Depending upon whether the given data is to be taken as the entire population (all values) or a sample from some larger population:
Population variance
Sample variance
Explanation:
This can be determined using standard built-in functions of a scientific calculator or a spread sheet (as below):
...or it may be calculated in steps as:
- Determine the sum of the data values
- Divide the sum of the data values by the number of data values to obtain the mean
- For each data value subtract the mean* from the data value to obtain the deviation from the mean**
- Determine the sum of the deviations of the data values from the mean.
For population variance:
- Divide the sum of the deviations by the number of data values* to obtain the population variance**.
For sample variance
- Divide the sum of the deviations by 1 less than the number of data values to obtain the sample variance