The equation of a straight line is b is slope a is intercept Seat belts. Least-squares regression line Make the sum of squared deviations of points from the line as small as possible. A lurking variable is one which has an important effect on the response but is not included in the explanatory variables. The correlation coefficient measures the strength of the linear association between two variables. Does not distinguish explanatory from response variable.
Positive r is positive association, negative r is negative association.
2 is the fraction of the variation in y that is explained by regression on x. Averaged data Age and blood pressure.