It's simple, because pay attention to what is written on page 393. R 1y and r2y in the equation represent the correlation coefficient between the dependent variable and the independent variable. Pay attention to the correlation coefficient. Therefore, the related concepts and calculation methods of education index group 1 and monthly average income group 2 are exactly the same as those of education index group 1, so r 12 is equal to.

R 1 1 and r22 are related conceptual coefficients of education index group 1 and education index group 1, and related conceptual coefficients of monthly average income group 2 and monthly average income group 2. The correlation coefficient must be the same, so the correlation coefficient is 1. If expressed as a percentage, that is to say, the percentage of association between oneself and oneself must be 100%, and ontology is ontology.

The calculation methods of r 12 and r2 1 are calculated according to the formula in the second section of chapter 5, and different r formulas have errors.