Before you can interpret the numerical value of r, you need to determine if it was appropriate to calculate r to begin with. The Pearson correlation coefficient, r, describes the strength and direction of a linear relationship between two variables. The first step in exploring a linear relationship is to generate the scatterplot, which you learned about in the previous section.
New Smog Check Test Smog Check Program's Updated Test Technology Californians getting Smog Checks today may notice that the traditional tailpipe test used for many years has been replaced by a quicker, computer-based test for gasoline-powered cars model-year 2000 and newer, and for most diesel vehicles that are model-year 1998 and newer.
Here are the top tips from our experts to prepare your car for a smog check: 1. Clear that Check Engine light. If your car displays a Check Engine light, that's an automatic smog check failure. You'll need to get a diagnosis and fix before you test.