# graphing distributions of single variables

# get data
# http://www.robin-beaumont.co.uk/virtualclassroom/book2data/pain_medication.dat



mydataframe <- read.delim("http://www.robin-beaumont.co.uk/virtualclassroom/book2data/pain_medication.dat",
 header=TRUE)
 names(mydataframe)
# or locally
# mydataframe <- read.delim("D:\\web_sites_mine\\HIcourseweb 
 new\\book2data\\pain_medication.dat", header=TRUE)
names(mydataframe)
str(mydataframe)
 
names(mydataframe)
#[1] "age"       "gender"    "health"    "treatment" "dosage"    "status"   
#[7] "time"     

with(mydataframe, Hist(age, scale="frequency", breaks="Sturges", col="darkgray"))
#density plots

library(car)
densityPlot( ~ time, data=mydataframe, bw="SJ", adjust=1, kernel="gaussian")
densityPlot( ~ age, data=mydataframe, bw="SJ", adjust=1, kernel="gaussian")

# avoiding the use of the car package;
plot( density ( mydataframe$age)) 
plot( density ( mydataframe$time))