R notes for Activity 8-3: Matching Game
Although the book says that the data are stored in the file
Matching, we've separated the data into
three separate files:
MonopoloyPrices.csv,
SnowfallAmounts.csv,
and
QuizPercentages.csv.
All are stored in the standard data directory for this course.
Recall that you can read a file into a frame with a command like
MonopolyPrices = read.csv("/home/rebelsky/Stats115/Data/MonopolyPrices.csv")
You should be able to figure out the commands to read the other two
data sets.
We need to load an appropriate library to do dotplots, but otherwise
it remains straightforward. Particularly since we do not plan to use
these graphs for anything but a quick observation, we don't even need
to fool with axis labels.
library(BHH2, lib="/home/rebelsky/Stats115/Packages")
dotPlot(MonopolyPrices, main="Prices of Monopoly Properties")
You might note something a bit strange about this command.
Traditionally, we use dotPlot with vectors.
And, if you think about it carefully, MonopolyPrices is
a data frame, rather than a vector. So, why does the command work?
Apparantly, R is smart enough to treat a data frame with one column
as a vector, at least for this plot.
If, however, you want to create a histogram, you'll need to
extract the column (which is also called
MonopolyPrices).
hist(MonopolyPrices$MonopolyPrices)
Here's a fine-enough grained histogram that it replicates the dotplot.
hist(MonopolyPrices$MonopolyPrices, breaks=seq(from=0,to=500,step=25))
