Currently, I'm working building a regression model for the prediction of various financial variables. After data collection, I'm now looking into qqplots to determine differences in distributions of the independent variables. The picture added is an example of a result obtained using a QQplot.
Now I need to add a regression line and calculate the R^2, to determine which data transformation (log, quadratic, ...) I should apply.
This is de line that creates the QQplot:
qqplot(Xvar, Yvar, plot.it = TRUE, xlab = Xvar, ylab = Yvar, xlim=c(-5, 30),
ylim=c(0, 100000000), main = QQPlot)
Can you, please, help me with this?
Thank you!