# Read in data Diarrhea
DiaData <- read.delim("http://myweb.uiowa.edu/pbreheny/data/diarrhea.txt")


# Boxplot
boxplot(DiaData$Stool ~ DiaData$Group, col = rainbow(2), main = "Effect of bismuth salicylate")


# Summary Statistics

#Find n in each group
table(DiaData$Group)

#Find mean of each group
by(DiaData$Stool, DiaData$Group, mean)

#Find standard deviation of each group 
by(DiaData$Stool, DiaData$Group, sd)



# Equal Variance t test

t.test(DiaData$Stool~DiaData$Group, var.equal = TRUE)



# Unequal Varaince t test
t.test(DiaData$Stool~DiaData$Group, var.equal = FALSE)


# read in data heart
heart <- read.delim("http://myweb.uiowa.edu/pbreheny/data/infant-heart.txt")