##############################
#
# Script: assignment01a.R
#   Answers to the first 
#   homework assignment
#
##############################


# Read in the data

ht <- read.csv("http://courses.kvasaheim.com/pols6123/data/studentHeight.csv")
names(ht)
summary(ht)
attach(ht)


#####
# Problem 1

boxplot(height~sex, las=1, xlab="Gender", ylab="Height (in)")

t.test(height~sex, alternative="greater")


#####
# Problem 2

# Check assumption of Normality using boxplots
boxplot(height~sex, las=1, xlab="Gender", ylab="Height (in)")

# or using histograms
hist(height[sex=="Male"])
hist(height[sex=="Female"])

# or using the Shapiro-Wilk test
shapiro.test(height[sex=="Male"])
shapiro.test(height[sex=="Female"])

# in each of these, Normality seems reasonable 
t.test(height~sex, alternative="greater")