How to get the T-83 or T-83 Plus to do a Linear Regression.
What the calculator is doing is that it’s drawing the best possible straight line through data points. It’s making sure that the sum of the errors of points above the line cancels with the sum of the errors of point below the line. It then gives you the slope(a) and y intercept(b) for such a line. The r value gives you an idea of how close your points are to the line. The closer r is to one, the better the data points are.