1.2 Basic Stat commands (Albert) (pp 2-8).txt

##Basic statistics on "studentdata"

##we use studentdata in LearnBayes

library("LearnBayes")
#access the data by:

data(studentdata)

#to see variable names

studentdata[1, ]

#to see the top 5 observations:

head(studentdata)

#to see the bottom 5 observations:

tail(studentdata)

#attach (make visible) the data to the R environment

attach(studentdata)

#without attach, you need to use studentdata$"variable name" for all requests

#to tally responses in categorical variable Drink

table(Drink)

#without using attach, you need to use table(studentdata$Drink)

#construct bar plot

barplot(table(Drink), xlab = "Drink", ylab="Count")

#compute new variable

hours.of.sleep=WakeUp-ToSleep

#descriptive statistics

summary(hours.of.sleep)

#construct histogram

hist(hours.of.sleep,main="")

#compare with

hist(hours.of.sleep)	#see change in heading

#get boxplot of hours.of.sleep per gender

boxplot(hours.of.sleep~Gender, ylab="Hours of Sleep")

#create variable per category

female.Haircut=Haircut[Gender=="female"]

male.Haircut=Haircut[Gender=="male"]

#get summary of these new variables

summary(female.Haircut)
summary(male.Haircut)

boxplot(Haircut~Gender,ylab="Haircut")

#R commands for studying relationships

plot(jitter(ToSleep),jitter(hours.of.sleep))
#Try removing jitter

plot((ToSleep),(hours.of.sleep))

fit=(lm(hours.of.sleep~ToSleep
fit
abline(fit)