# RScript from AIS Workshop on R
# By David Schuff, Professor of MIS, Temple University

# Install required packages as needed
if (!require("psych")) { install.packages("psych")
  require("psych") }
if (!require("Hmisc")) { install.packages("Hmisc")
  require("Hmisc") }

teamData <- read.csv("2009BaseballTeamStats.csv")
summary(teamData$BattingAvg)
summary(teamData$WinningPct)

# Descriptive statistics by league
describeBy(teamData$Runs,teamData$League)

# t-test for differences in average runs by League
t.test(teamData$Runs~teamData$League)

# Create the scatterplot
plot(teamData$BattingAvg,teamData$WinningPct, xlab="Batting Average",
         ylab="Winning Percentage")
title("Do Teams With Better Batting Averages Win More?")

# Draw the trendline
reg1 <- lm(teamData$WinningPct~teamData$BattingAvg)
abline(reg1)

# Check for the statistical significance of the correlation
rcorr(teamData$BattingAvg,teamData$WinningPct)