DATA MINING
Desktop Survival Guide
by Graham Williams

## Line and Point Plots

A dot plot can be extended to draw lines between the dots! We use a simple dot plot to compare two sets of data. The points record (fictional) percentages of patients recorded as dying within 30 days and within 6 months of some procedure. Once again, a plot is first created for death6m. In this case we have both points and lines (type="b"), solid lines are used (lty=1), and a small square is used to plot points (pch=0). The rest of the plot is then constructed by adding a plot for death30, adding a box around the plot, and adding two axes and a legend.

[width=0.6]rplot-dot

 ```pdf('graphics/rplot-dot.pdf') dates <- c('Jul-98', 'Aug-98', 'Sep-98', 'Oct-98', 'Nov-98', 'Dec-98', 'Jan-99', 'Feb-99', 'Mar-99', 'Apr-99', 'May-99', 'Jun-99') death30 <- c(2.02, 1.53, 2.73, 3.09, 2.37, 2.60, 3.87, 6.11, 3.23, 4.52, 4.27, 1.40) death6m <- c(1.52, 2.55, 3.28, 1.55, 0.95, 3.65, 4.42, 5.68, 8.29, 15.08, 32.70, 75.52) plot(death6m, type='b', xlab='Month', ylab='Percentage', lty=1, pch=0, axes=FALSE) lines(death30, type='b', lty=2, pch=1) box() axis(1, at=seq(1, length(dates)), labels=dates) axis(2, at=seq(0, 100, 10)) legend(1, 60, c('Deaths before 30 days', 'Deaths before 6 months'), lty=c(2, 1), pch=c(1, 0)) dev.off() ```

http://rattle.togaware.com/code/rplot-dot.R