###Lecture 25 - Code for running an ANOVA in R

### import data

datum=read.csv(file.choose())
datum$X=as.factor(datum$X) #Tell R that the x variable is categorical
### replace 'X' with variable name
head(datum)

### Run the LM


results=lm(Y~X,data=datum) ### Run an ANOVA using the general linear model
### Note: replace 'Y' in above statement with Y variable
### Replace 'X' in above statement with X variable
confint(results) ### get the results the usual way


### Plot results

plot(Y~X,data=datum)
### Note: replace 'Y' in above statement with Y variable
### Replace 'X' in above statement with X variable


### Change the reference category

results4=lm(Y~relevel(X,ref="Cat1"),data=datum) 
### replace the x variable you want to change with the 'relevel' function
### Including in relevel function, arguments for category being releveled (X)
### and what category you want to be the reference (ref="whatever category you want")