# Testing hypothesis for equality of medians for more 
#than two related populations 

#Set working directory
setwd("~/Dropbox/ISI SCB/Data sets")

# read in csv file
rrr <-read.csv("ratings.csv", TRUE)

Rating <- rrr$Rating
Restaurant <- rrr$Restaurant
Rater <- rrr$Rater

#Display the data in box plots
boxplot(Rating~Restaurant)
boxplot(Rating~Rater)

#Friedman Test: Two-Way Analysis of Variance by Ranks
friedman.test(Rating, Restaurant, Rater)