Introduction*to*R*******************************************************************201602017!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!Cheatsheet*–*Analysis*of*Variance!
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Introduction*to*R*
201602017*
Cheat*Sheet*–*Analysis*of*Variance*(2*way*factorial*anova,*actually)*
*
Dear*R*learner,**This*is*a*work*in*progress,*so*please*do*not*consider*this*complete.**All*suggestions*and*additions*
are*very*welcome*–*cb.*
!
Cheat!sheet!by!example!
Response!Y!=!yvar!
Factor!I!predictor!is!drug!(1=control,!2=tx,!3=other)!
Predictor!II!predictor!is!season(1=winter,!2=spring,!3=summer,!4=fall)!
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!
Get*your*data*into*R*(3*ways)*
setwd(“/Users/cbigelow/Desktop/”)
install.packages(“openxlsx”) # Excel data (.xlsx)
library(openxlsx)
dat <- read.xlsx(“myexceldata.xlsx.dta”)
install.packages(“readstata13”)
library(readstata13)
dat <- read.dta13(“mystatadata.dta”, convert.factors=FALSE) # Stata data (.dta)
install.packages(“haven”)
library(haven)
dat <- read_sas(“mysasdata.sas7bdat”) # SAS data (.sas7bdat)
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*
Label*factor*levels.*
levels(dat$drug) # List levels
levels(dat$drug) = c(“control”, “tx”, “other”) # Give levels names
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!
!
Tell*R*that*the*predictors*are*FACTORS*
dat$drug <- as.factor(dat$drug)
dat$season <- as.factor(dat$season)
