Hey everybody, I have a matrix with three columns.

I want to plot two columns (independent variable) against one column (the
defendant). This is my code and the error associated with it:

plot(p, q, data=columns)

> plot(pprime,q, add=TRUE)
Warning messages:
1: In plot.window(...) : "add" is not a graphical parameter
2: In plot.xy(xy, type, ...) : "add" is not a graphical parameter
3: In axis(side = side, at = at, labels = labels, ...) :
  "add" is not a graphical parameter
4: In axis(side = side, at = at, labels = labels, ...) :
  "add" is not a graphical parameter
5: In box(...) : "add" is not a graphical parameter
6: In title(...) : "add" is not a graphical parameter

How do I resolve this problem?

thanks!

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