Compare 7 different conditions with ANOVA

alfred

New Member
#1
Hello there,

In my SPSS dataset each subject is assigned a certain score upon 7 different conditions: therefore in SPSS I have 7 columns and 20 lines, each line representing a subject/case, each column reporting a value (score).
The data is normal and I want to compare the scores between the different conditions.

I understand that if I had just 2 conditions I would run a (paired samples) T-Test, while in my case I should run an ANOVA to compare all the 7 seven conditions (and then, if I obtain significance, run a post-hoc test).
If I try to run a one way ANOVA in SPSS (Analyze->Compare Means->One-Way ANOVA), I'm asked for the grouping "Factor", however I don't have a factor and therefore I cannot run the ANOVA (the "OK" button is disabled). Am I running the correct ANOVA? What do I miss?

Thank you in advance for your help
 

RobH

New Member
#3
You sound like you have a repeated-measures design (i..e the same participant provides data for all seven conditions) in which case you need to use Analyze>General Linear Model>Repeated Measures. It would help to know what sort of thing your seven conditions are. Is it the same measure taken at seven different time points? What SPSS needs to know is how the 7 different conditions are related to each other - are they manipulations of one or more different underlying factors?
 

alfred

New Member
#4
Thank you very much for your replies.
The 7 different conditions in my experiment are manipulation of one underlying factor...
 

RobH

New Member
#5
When you do the analysis in SPSS, it will ask you to put in the name of the factor and the number of levels (7 in your case) - you then have to assign the relevant columns in your dataset to the different levels of the factor that you created in SPSS, so that it can complete the analysis properly