Mauchly's Test of Sphericity with Repeated Measures ANOVA in SPSS

[@coraliehoney]

I'm analysing the data for my 4th year Undergrad Honour's Project right now. You really helped! This video explained everything so clearly, thank you!

[@maxtindall3651]

Great video. I've been seaching for ages on what to do if sphercity is violated and many textbooks and help vidoes don't explain it very well. But you made it simple and easy to understand

[@DrGrande]

I'm glad you found the video useful. Thanks for watching.

[@Chris256C]

Thanks for explaining this, really helpful.

[@gazesalso645]

I'm doing a repeated measures ANOVA. Would it be correct to say that if a correction is applied, say Greenhouse-Giesser, then if the F-statistic is significant one goes on to check pairwise comparisons though the sphericity assumption had not been violated?

[@louisewatts1269]

This video is so helpful! Thank you!!

[@MrWubly]

When is the bonferoni correction made? My professor has told is to use it for repeated measure Anovas

[@ritat1576]

Hello, I am wondering what to do if you have two independent variables which have both violated Mauchly's test, however, one has also violated the Greenhouse Geisser correction and the other one did not. In this case would I use two different corrections or would I use the Huynh-Feldt correction for both?
Thank you

[@simplythoko1959]

Great tutorial, thank you. Most people on here don't actually mention what to do if the Mauchler's is violated. I violated my Mauchler's test and got a value of .702 so I guess I have to use the Greenhouse geisser. How would I report that in the results. Do I mention that the Mauchler's test was violated and report the Greenhouse geisser instead?

[@Crimsonyte21]

If you wouldn't mind, could you explain why we look for 0.75? I'm using you're explanation for my dissertation :)

[@StatistikamPC_BjoernWalther]

Check this: health.uottawa.ca/biomech/courses/apa6101/Repeated%20Measures%20ANOVA.pdf

[@ME-ft2bd]

@@StatistikamPC_BjoernWalther could you please send me the link or post it again. I clicked on it and it was not working unfortunately

[@dedeosman2198]

hi, I have a question? what about lower-bound value? could you exlain also what is this value about? when it is used? if I violate shpericity, greenhouse-geisser and huyhn-feldt correction? shoud I use lower-bound value or quit doing repeated ANOVA? thanks..

[@mdharunarrashid3038]

Dear Grande, Thank you for a nice explanation. I have data1 from using target drug and data2 from placebo treatment and I had only one time point for each drug(placebo or target drug). So I have only 2 set of data, you mentioned we need 3 set of data as I understood. When I am performing SPSS v24, repeated anova then I am getting Mouchly's test value. will this test value be acceptable and should I use corrections in this case?

[@jasminedequin4044]

Thank you so much! :)

[@lucamuss6113]

what if the mauchly's p-value is .000?

[@TheLenessa]

+todd Grande awesome video. I have a sample size of 22 with even groups. I am comparing their pre/post test and I am not getting data for the p value for Mauchly's. Is this because of my sample size?

[@julp]

+LunestatheGreat Hello, "Difference scores computed between two levels of a within-subjects factor must have the same variance for the comparison of any two levels. (This assumption only applies if there are more than 2 levels of the independent variabl"You have just 2 independent variables for a repeated measurements test, named pre/post test if i am correct. So this means you can't compute a sphericity.

[@julp]

More specifically: " It should be noted that sphericity is always met for two levels of a repeated measure factor and is, therefore, unnecessary to evaluate.[1] Moreover, statistical software, such as SPSS, will not provide output for a test of sphericity for two levels of a repeated measure factor."

[@amparanyameyie5719]

You should have used a dependent t-test because you had two test - pre and post tests results

[@beyondgirl]

very helpful