if there is a linear relationship between happiness and income how to explain the relationship between income and happiness when comparing two linear models what is the answer can you test a linear regression with an example of an individual what is the relationship between the income and the happiness how to test whether regressions work in both groups can the linear model explain happiness when to use a linear regression model how to test whether a linear model fits together how to test if a relationship between happiness in two regressions is better than a single model? how to determine whether the relationship between happiness and income is the best one in regression how do you tell if you have a unique model how to tell if two regression models are better how to test whether a linear model is better than a single regression what are the differences between a linear model and a single model? how do you test whether a linear model is better than a single model why is there a relationship between happiness and income how does regression explain can two regressions be done separately to explain the same data what is the difference between a single linear model and a unique linear model?