SPSS one-way ANOVA - (Aug/17/2009 )

Hi,I want to compare difference among eight groups using One-Way ANOVA in SPSS,but in the test of homogeneity of variances p<0.05,it is equal variances not assumed,so can I use One way ANOVA for further analysis? How about post hoc multiple comparisons?Thanks.

Will transforming the data, eg log scale, work? I’ve read that deviations from homogeneity can be tolerated if there are equal numbers of samples in each of your groups; but, like all statistics, there is no consensus. SPSS has a range of post hoc tests available when equal variances cannot be assumed (Tamhane's T2, Dunnett's T3, Games-Howell, and Dunnett's C) so presumably they recognise that we often have to precede the best we can with dodgy data.

Of those four post hoc tests above I would guess that Tamhane’s would be best for you, Dunnett’s tend to be used when you are comparing groups against a reference rather than against each other (but I’m pushing my knowledge of stats to the limit so double check ). In practice I tend to select a number of post hoc tests and make sure they all give similar answers or that I can give an explanation of any differences.