CODEWITHSUNDEEP
ranova
pmcurr15
pmcurr15

Reputation: 3

Anova Test- Separate Groups with Two Factor Comparison

Good morning, I am trying to run some ANOVA tests on my dataset (using R) and I keep getting errors. I am trying to compare the average percentage of correct responses, as a factor of what "group" the subjects were in and what session/day it was. However, I have two separate conditions that I need to analyze separately.

So essentially, I need to compare PctCorrect in Condition 1, between groups and sessions and then do the same thing for condition 2.

I attempted using this code:

aov(ext$Pct.Correct[ext$Condition=="NC-EXT"]~ext$Group*ext$Session, data=ext)

and I got the following error:

Error in model.frame.default(formula = ext$Pct.Correct[ext$Condition == : variable lengths differ (found for 'ext$Group')

I ran this code to make sure that all of my values were even:

mytable <- table(ext$Session, ext$Group, ext$Condition) 
ftable(mytable)

And they were all the same value (which was to be expected), so I am not sure what's wrong.

I am very new to R so it's entirely possible that I am doing this completely wrong. Any help would be greatly appreciated.

Upvotes: 0

Views: 252

Answers (1)

Dave2e
Dave2e

Reputation: 24089

You are filtering the left side of the equation and not filtering the right side, thus the "variable length error".

You could try filter your dataframe in the data= option like this: 

aov(Pct.Correct ~ Group* Session, data=ext[ext$Condition=="NC-EXT",])

Upvotes: 1

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