Exploring Data in Two Dimensions

Line Plots of Selected Variables

If one or more variables are selected in a data table when you select Graph →Line Plot, then the Line Plot dialog box does not appear. Instead, a line plot is created. The rules for constructing the line plot are as follows:

  1. If one variable is selected, create a line plot of $Y$ versus $Y$.

  2. If exactly two variables are selected, the first is used as the Y variable and the second as the X variable.

  3. If $k>2$ variables are selected, then count the number of selected nominal variables.

    1. If no nominal variables are selected, create a line plot of $(Y_1, Y_2, \ldots , Y_{k-1})$ versus $Y_ k$.

    2. If there are nominal variables selected, then count the number of selected interval variables.

      1. If no interval variables are selected, then plot the first selected variable as Y, plot the second selected variable as X, and use the remaining selected variables as group variables.

      2. If there is exactly one interval variable, then plot it as Y if it was chosen first, and otherwise plot it as X. The first nominal variable is assigned to the X or Y role, and the remaining selected variables are used as group variables.

      3. If there are exactly two interval variables, then plot the first selected interval variable as Y, plot the second as X, and use the remaining selected variables as group variables.

      4. If there are more than two interval variables, then ignore the nominal variables and plot the interval variables as in rule 1.

Variables with a Frequency or Weight role are ignored when you are creating line plots.