I have a client/user who wants me to automate some analytical code done (by someone else) a few years ago. One of the tests that it does is equality of the variance in two groups. The current code uses the Equality ODS output table to get the needed stats (numerator and denominator degrees of freedom, the F statistic and the P-Value).
They've asked me to confirm that the test is Levene's test. I have not been able to find any documentation on what the actual test is. I did see discussion that PROC GLM can be used to get Levene's test.
So I have a two-part question:
- is the TTEST Equality output using Levene's test?
- if not, what test is it using?
TIA, for any input/advice.
DonH
PROC TTEST uses a folded F-test to test the equality of variances.
You would need PROC GLM to get Levene's test.
PROC TTEST uses a folded F-test to test the equality of variances.
You would need PROC GLM to get Levene's test.
Thx Paige. That make perfect sense. I noticed the output data set made reference to a folded F, but my stat skills are pretty rusty and did not realize what that meant,.
Thx again!
Available on demand!
Missed SAS Innovate Las Vegas? Watch all the action for free! View the keynotes, general sessions and 22 breakouts on demand.
ANOVA, or Analysis Of Variance, is used to compare the averages or means of two or more populations to better understand how they differ. Watch this tutorial for more.
Find more tutorials on the SAS Users YouTube channel.