Normality test violations


New Member
I have a small sample size (N=26) made up of three groups (n=11, 6 & 9).

Whilst running a mixed design ANOVA I have violated both Box's Test of Equality of Covariance (p = .025). I continued my analysis and found that the pre condition also violates Levene's test (p = .016).

Is this a problem?

I am new to stats and have searched high and low online without any luck... Any help is much appreciated!

Thank you



Super Moderator
It sounds like your concern is with the homogeneity of variance assumption, not the normality assumption....?

You mention a mixed design - what is the within-subjects factor?
Yes it seems my problem is with the homogeneity of variance assumption, as I understand it that is what is being tested by Levenes Test of Equality of Error.

I made a mistake regarding Box's Test of Equality and Covariance, there is no violation to this test as the significance level is .001 and in my test p = .025.

My design is this:
3 IV = RR n=6, RX n=11, XX n=9
2 conditions = pre and post test

So am I correct in saying that the within-subjects factor is the testing time or stage (pre/post)?

Thank you!