Drag the points to move them. Check "correlation". What happens to the correlation when you move a point? Check "Fit your line". Drag the line to move it up or down. Drag the "x" to rotate the line. Try to find the line of best fit by minimizing the Sum of Squared Errors (SSE). Check "Fit Least Squares Line" to see the line of best fit. How does it compare to your line? What happens to the line of best fit when you move a point?