case of the diagnostic tests   this model looks reasonably okay, we haven't got erm significant serial correlation, we haven't breached  form, we have reasonably normally distributed residuals, right, test for hetero skilasticity that just a test to see whether the residuals are growing over time, right,hetero skilasticity is where we have non constant, non constant variance  of our, of our error term  right, and very often you, you find that the variance through the residuals, something like that  the residuals will look like that, i think, they're growing systematically over time, right, these are homo skilastic right, and these are hetero skilastic right, residuals and again we wouldn't want to have a model of hetero skilastic residuals, right, simply because that violates one of the assumptions on which the blue properties  are based.