After gaining insight into the general relationship of the variables, a quantitative analysis method may be more easily chosen:
User Interface
To create a scatterplot, select "Scatterplot" from the "Analysis Tools" menu. A dialog box will appear that allows the user to enter plotting parameters. Select the data set of interest from the pull-down menu, or browse for a tab-delimited text file. The Data Subsetting tab can be used to select a subset of the data file by choosing a variable from the pull down menu and then selecting the levels of that variable to include. You can hold down the <CTRL> key to select multiple levels. A separate plot will be produced for each unique setting of the subsetting variables. Select a variable to plot on the x-axis and a different variable to plot on the y-axis. A regression fit can be overlaid on the scatterplot. If Linear Regression Line is selected, a straight line fit is drawn. If Loess Smooth is selected, a nonparametric loess fit is drawn. You may change the axes labels and plot title by typing them in the Labels dialog. The output is simply the scatterplot graph with any overlaid fits requested.
To learn about correlation analysis, see cor.
To learn about linear regression, see lm.
To view the help file for the general R plotting function, see
plot
.