Long time reader, first time poster. I'm doing an observational study and have gotten into unknown waters in both statistics and R (beginner in both).
(1) I have 2-categorical variable (species) and roughly 4000 rows with behavior (11 classes, reconfigured in to 'foraging' or 'not-foraging').
I'm trying to figure out if the two groups differ in their behavior My professor told me to use proportions of the behavior to do a t-test of the means of the two groups(species).
I've spend a week finding nothing but "you shouldn't do that" and "you can't do that" anywhere I look or ask online.
I'm at a loss for words - We're looking at basic university level, so I am not expected to figure out the secrets of the universe here.
I found prop.test, which I applied to the two groups, but I'm unsure of that actually shows, what I think it shows and I read somewhere that a
prop.test is actually a z-test (I don't understand the difference).
(2) Furthermore I have another 3-categorical variable (vegetation type).
I'm trying to figure out if the behavior differs across vegetation type (never mind species for now - I can always do them seperately, if necessary).
I was told I could do a simple, linear ANOVA type of model (
lm function in R), again; using the proportions of behavior as response and the vegetation type as predictor.
I've reached exactly the same dead-end as with question (1): Apparantly, it can't be done. I have found a few comment in different threads (present site included) stating that you CAN do a simple linear anova using percentage/proportion data, but I haven't found any actual examples of the procedure to do so and therefore I haven't gotten any further..
- Have I misunderstood "Proportions"?
- Is there a way of transforming my count-data into proportions and do a t-test?
- Does anybody have any suggestions?
- Is there any way of transforming my data into proportions and do an ANOVA?
I'm desperate and will appreciate any help/suggestions whatsoever.