control.data <- scan('http://math.uttyler.edu/nathan/classes/statistics/data/reading-control.data')

# a numerical summary
summary(control.data)
sd(control.data) # standard deviation

hist(control.data)
boxplot(control.data)

# how to do a confidence interval?
t.test(control.data)
t.test(control.data,conf.level=.99)

# hypothesis test?
#H0: mean  =  40
#H1: mean =/= 40
t.test(control.data,mu=40)

#H0: mean <= 35
#H1: mean > 35
t.test(control.data,mu=35,alternative='greater')

#H0: mean >= 50
#H1: mean < 50
t.test(control.data,mu=50,alternative='less') 

treat <- scan('http://math.uttyler.edu/nathan/classes/statistics/data/reading-treatment.data')

boxplot(control.data,treat)

# a confidence interval for mu.treat - mu.control
t.test(treat,control.data,conf.level=.90)

t.test(treat,control.data,conf.level=.90,var.equal=TRUE)

# H0: mu.treat <= mu.control
# H1: mu.treat > mu.control

t.test(treat,control.data,alternative='greater')

# reading in more data (this one is from the HW)
spanish.test <- read.table('http://math.uttyler.edu/nathan/classes/statistics/data/spanish-test.data',header=TRUE)

plot(spanish.test)

# a little bit about name-spaces
spanish.test    #prints the data frame
pre.test #error
spanish.test$pre.test  #this is what I wanted

#so:
boxplot(spanish.test$pre.test,spanish.test$post.test)

# to avoid typing 'spanish.test$' in front of everything:
attach(spanish.test)
pre.test   # no error
post.test  # no error
boxplot(pre.test,post.test)
detach(spanish.test)
pre.test  # error again