>The OLS fitted line is displayed in a scatter plot only if the slope >coefficient is significant at the 10 percent level. (If you want an >actual versus fitted graph regardless of the significance of the fit, >you can estimate an OLS model and explicitly request such a plot via the >menus). > > Good to know, because during lectures I couldn't explain to my students why the line was sometimes there, sometimes not. To be honest, I think it's better to not make it dependent on significance. At the stage of plotting without estimating a model, I would never have guessed that already some testing was going on.