Created
October 6, 2019 20:48
-
-
Save SwampThingPaul/09f76573873c0600115fd6b0e103f780 to your computer and use it in GitHub Desktop.
Weekend of a Data Scientist in R
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
# R version of https://medium.com/cindicator/must-have-statistical-tests-for-any-data-scientist-weekend-of-a-data-scientist-4543f2c393cd | |
# Medium Article written by Alexander Osipenko (https://medium.com/@subpath) | |
# Fake Data (not the same data as article) | |
set.seed(123) | |
groupA=rnorm(1000) | |
groupB=rnorm(1100,mean=0.001) | |
# Quick Density plot | |
plot(0:1,type="n",xlim=c(-5,5),ylim=c(0,0.6),ylab="Density",xlab="Value",las=1) | |
with(density(groupA),lines(x,y,col="blue")) | |
with(density(groupB),lines(x,y,col="red")) | |
legend("topright",legend=c("Group A","Group B"),col=c("blue","red"),lwd=1,lty=1, | |
ncol=1,cex=0.8,bty="n",y.intersp=1.75,x.intersp=0.75,xpd=NA,xjust=0.5,yjust=0.5) | |
# Student’s t-test | |
shapiro.test(groupA); #normally distributed | |
shapiro.test(groupB); #normally distributed | |
t.test(groupA,groupB); # not significantly different | |
# Mann-Whitney’s U-test | |
groupA2=rnorm(100,sd=1.25)*runif(100) | |
groupB2=rnorm(100,mean=1.5)*runif(100) | |
# Quick Density plot | |
plot(0:1,type="n",xlim=c(-5,5),ylim=c(0,1),ylab="Density",xlab="Value",las=1) | |
with(density(groupA2),lines(x,y,col="blue")) | |
with(density(groupB2),lines(x,y,col="red")) | |
legend("topright",legend=c("Group A","Group B"),col=c("blue","red"),lwd=1,lty=1, | |
ncol=1,cex=0.8,bty="n",y.intersp=1.75,x.intersp=0.75,xpd=NA,xjust=0.5,yjust=0.5) | |
shapiro.test(groupA2); #not normally distributed | |
shapiro.test(groupB2); #not normally distributed | |
wilcox.test(groupA2,groupB2); # significantly different | |
# Fisher’s F-test | |
#using data from first example | |
dat=data.frame(val=c(groupA,groupB),groups=c(rep("A",length(groupA)),rep("B",length(groupB)))) | |
var.test(val~groups,dat) | |
# Bartlett’s test | |
dat2=data.frame(val=c(groupA2,groupB2),groups=c(rep("A",length(groupA2)),rep("B",length(groupB2)))) | |
bartlett.test(val~groups,dat) | |
# Levene’s test in R | |
library(car) | |
leveneTest(val~groups,dat) |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment