Compare variances

- What if you want to compare outputs of four groups?…The output is continuous data for all four,…and it could be dimensions, processing times,…or any characteristic that is continuous,…such as the time it takes for me…to complete a triathlon or deliver pizza.…If the theories you want to test…are about the variability or consistency of performance,…then you want to compare their standard deviations,…and variances.…Let's take a look at an example of this using Minitab.…Download and open the file VarianceTestData.mtw.…

This can be found in the exercise files.…Here we have that output of four groups,…these are all continuous data.…They could be processing times, delivery times.…And you want to test the consistency of performance…against a target standard deviation or variance.…Say, a target variance of 9.0.…So, the theory to be tested is that…the groups are more consistent than this…target variance of 9.0.…So we need to run one sample test on each of these groups.…

To do that, go up to Stat, Basic Stats, 1 Variance test.…