#  Summary statistics in R
## Ignore local file
# load("D:/web_sites_mine/HIcourseweb new/book2data/mwu_example1.RData")
##
load(url("http://www.robin-beaumont.co.uk/virtualclassroom/book2data/mwu_example1.rdata")) 
names(mydataframe)
str(mydataframe)
summary(mydataframe)

tapply(mydataframe$result, mydataframe$grouping, mean)
tapply(mydataframe$result, mydataframe$grouping,sum )
tapply(mydataframe$result, mydataframe$grouping,range )
tapply(mydataframe$result, mydataframe$grouping, quantile)
tapply(mydataframe$result, mydataframe$grouping, var)
tapply(mydataframe$result, mydataframe$grouping, sd)
tapply(mydataframe$result, mydataframe$grouping, median)
tapply(mydataframe$result, mydataframe$grouping, max)
tapply(mydataframe$result, mydataframe$grouping, min)

install.packages("psych", dependencies=TRUE)
library(psych)

describeBy(mydataframe$result, mydataframe$grouping)

xtabs(mydataframe$result ~ mydataframe$grouping )

###########  now  a three way one using a different dataset
# following to obtain my sample data:
# http://www.robin-beaumont.co.uk/virtualclassroom/book2data/pain_medication.dat

mydataframe <- read.delim("D:\\web_sites_mine\\HIcourseweb new\\book2data\\pain_medication.dat", header=TRUE)
names(mydataframe)
# [1] "age"       "gender"    "health"    "treatment"
# [5] "dosage"    "status"    "time"  

str(mydataframe)

library(psych)
describeBy(mydataframe$time, list(mydataframe$treatment, mydataframe$gender))