This is one sample standard deviation below the mean. And then we could do the same thing for the y variables. So the mean is three. And this is one sample standard deviation for y above the mean. And this is one sample standard deviation for y below the mean. And visualizing these means, especially their intersection, and also their standard deviations, will help us build an intuition for the equation of the least squares line. So generally speaking, the equation for any line is going to be y is equal to mx plus b, where this is the slope and this is the y-intercept.