On 2010-12-15 11:12, brianiphk wrote:
I'm trying to run an ANOVA in R and I have a problem: I used this command: anova(lm(time~age*region*facility)) Age, region, and facility are all factor levels, which has 2, 4, and 3 levels respectively. however, in the output (anova table), it states that the df is 1 for all three factors, which should be 1, 3, and 2 respectively. Can anyone tell me if it is necessary to declare the factors as class before it can run correctly? Or is there any other problem?
Yes and Yes. 1) your 'factors' are obviously coded numerically - never a good idea. See ?factor on how to convert them. 2) why are you using lm()? Use aov(). See ?aov, ?anova Peter Ehlers
I attached the data set as shown below. Thank you very much! ( http://r.789695.n4.nabble.com/file/n3089686/data1.csv data1.csv
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