I have acquired data with multiple variables that I need to test. My dependent variable, Seed number, is tested between Ecotypes but also between Treatments (hot and cold). I need to see whether Seed Number between Ecotypes is the same when different Treatments are applied. In other words I might expect to see a difference in Seed Number between Ecotypes in the hot but not cold. The test is complicated by the fact that multiple repeats were taken that are likely to be significantly different and therefore grouping the repeats may confound the results.

I am using SPSS so any help there would be useful.


2 Answers 2


You may try an approach similar to the store-price example on this page: http://ww2.coastal.edu/kingw/statistics/R-tutorials/repeated.html

If your variable (column) names are SubjectNo, SeedNo, Ecotype and Treatment, the statement can be:

aov.out=aov(SeedNo ~ Treatment*Ecotype + Error(SubjectNo/Treatment), data=mydata)

Edit: Actually, following simpler form may be right for this situation:

aov.out=aov(SeedNo ~ Treatment*Ecotype, data=mydata)
  • $\begingroup$ Unfortunately it's not repeated measures. I wonder if its two-way ANOVA focussing on the interaction between Ecotype*Treatment $\endgroup$ Apr 16, 2015 at 15:27
  • $\begingroup$ Please see the edit above. $\endgroup$
    – rnso
    Apr 16, 2015 at 15:32

If you are interested in using SPSS, you can use ANCOVA for your objective.

DV-Seed number (continuous)

IDV- Ecotypes (categorical)

By controling for

Covariate- Treatment ( categorical)


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.