##########
##
# Reading the data into R:

ff <- tempfile()
cat(file=ff, "
 1 NORTH 93 33.00 
 2 NORTH 164 51.50 
 3 NORTH 138 43.10 
 4 NORTH 125 23.25 
 5 NORTH 129 24.50 
 6 NORTH 65 18.75 
 7 NORTH 193 43.50 
 8 NORTH 68 12.00 
 9 NORTH 139 31.75 
 10 NORTH 81 20.40 
 11 NORTH 73 16.00 
 12 NORTH 130 25.50 
 13 NORTH 147 44.00 
 14 NORTH 51 9.20 
 15 NORTH 56 15.40 
 16 NORTH 61 6.75 
 17 NORTH 115 11.40 
 18 NORTH 70 24.75 
 19 NORTH 44 8.25 
 20 NORTH 44 9.80 
 21 NORTH 63 14.30 
 22 NORTH 133 31.50 
 23 NORTH 239 41.50 
 24 NORTH 133 24.50 
 25 SOUTH 35 20.00 
 26 SOUTH 30 25.00 
 27 SOUTH 42 35.00 
 28 SOUTH 30 17.50 
 29 SOUTH 21 18.00 
 30 SOUTH 79 30.25 
 31 SOUTH 60 28.50 
 32 SOUTH 63 19.50 
 33 SOUTH 53 28.00 
 34 SOUTH 131 52.00 
 35 SOUTH 155 61.50 
 36 SOUTH 34 27.25 
 37 SOUTH 58 23.75 
 38 SOUTH 55 13.00 
 39 SOUTH 105 39.25 
 40 SOUTH 66 24.40 
 41 SOUTH 70 29.00 
 42 SOUTH 56 26.25 
 43 SOUTH 38 10.90 
 44 SOUTH 43 22.50 
 45 SOUTH 47 33.25 
 46 SOUTH 157 65.25 
 47 SOUTH 100 51.50 
 48 SOUTH 22 15.60 
 49 SOUTH 105 52.00
", sep=" ")

options(scipen=999) # suppressing scientific notation

tree <- read.table(ff, header=FALSE, col.names=c("obs", "side", "rings", "circum")) 
  
# Note we could also save the data columns into a file and use a command such as:
# tree <- read.table(file = "z:/stat_516/filename.txt", header=FALSE, col.names = c("obs", "side", "rings", "circum"))

attach(tree)

side <- factor(side)

# The data frame called tree is now created.
#########