least_squares_plots:
  R version 3.4.4 (2018-03-15) 
  Compare 15 data points with the least squares line
    y = A * x + B
  which minimizes the root-mean-square error.
  The data is actually perturbed values of a quadratic
  formula, which is shown for comparison:
    y = 1/2 x^2 + 1

  Graphics saved as ' least_squares_plots.png '

least_squares_plots
  Normal end of execution.