# Bears Example -- bears.R source code

# Read data from input file.
raw <- read.fwf(file="bears85.txt", 
	                widths=c(3, 20, 3, 1, 1, 3, 4, 3, 3, 14),
	                header=FALSE,
	                skip=2,
	                col.names=c("JerseyNumber", "Name", "Pos", "HtFt", "dash",
	                	          "HtIn", "WtLbs", "Age", "YrsInPros", "College"),
	                strip.white=TRUE)

# Convert height and weight to metric.
height <- (raw$HtFt * 12 + raw$HtIn) * 0.0254
weight <- raw$WtLbs * 0.45359237

# Create data frame.
bears <- data.frame(Height=height, Weight=weight, Pos=pos)

# Print bears data frame.
print(bears)

# Show means and standard deviations of heights and weights
cat("Mean of height:\n")
print(mean(bears[ , "Height"]))
cat("Mean of weight:\n")
print(mean(bears[ , "Weight"]))
cat("Standard deviation of Height:\n")
print(sd(bears[ , "Height"]))
cat("Standard deviation of Weight:\n")
print(sd(bears[ , "Weight"]))

# Show covariance matrix of height and weight
cat("Covariances and correlations:")
print(cov(bears[ , c("Height", "Weight")]))
print(cor(bears[ , c("Height", "Weight")]))

# Create scatterplot of weight vs. height
pdf("bears.pdf")
plot(bears$Height, bears$Weight, 
     main="1985 Bears Dataset",
     xlab="Heights of Players (meters)",
     ylab="Weights of Players (kilos)")
            
# Create variable team, where offense=O, kicker=K, and defense=X; add it
# to the bears data frame.
pos <- raw$Pos
team <- rep("", length(pos))
team[pos == "QB" | pos == "RB" | pos == "FB" | pos == "WR" |
     pos == "C"  | pos == "G"  | pos == "T"  | pos == "TE" ] = "O"
team[pos == "K"  | pos == "P"] <- "K"
team[team != "O" & team != "K"] <- "X"
bears$Team <- team
print(bears)

plot(bears$Height, bears$Weight, pch=bears$Team,
     main="1985 Bears Dataset; Offense=O, Kicker=K, Defense=X",
     xlab="Heights of Players (meters)",
     ylab="Weights of Players (kilos)")

# Redirect graphics output back to windows default.
dev.off( )