l.hydro <-
  scan('http://math.uttyler.edu/nathan/classes/statistics/data/hw2-add.data')

summary(l.hydro)
boxplot(l.hydro)
#boxplot(l.hydro,rnorm(30,mean=mean(l.hydro),sd=sd(l.hydro)))

hist(l.hydro)

t.test(l.hydro)

#	One Sample t-test
#
#data:  l.hydro 
#t = 3.6799, df = 9, p-value = 0.005076
#alternative hypothesis: true mean is not equal to 0 
#95 percent confidence interval:
# 0.8976775 3.7623225 
#sample estimates:
#mean of x 
#     2.33 

# we are 95% confident that the average number of extra hrs of sleep of
# l.hydro takers is between .90 and 3.76

t.test(l.hydro,conf.level=.9)
# we are 95% confident that the average number of extra hrs of sleep of
# l.hydro takers is at least 1.17.