英语课调查：收入和幸福有没有关系？为什么？（有满意回答加分）

yes. they are correlated in either positive way or negative way.
income increase means we have more money to spend, such as favorite car,house,clothes,food and so on. your wishes have been reached, your happiness have been increased as well.this is the positive correlation.

in contrast, income increase lead to more workload which makes you busier than ever. you won't have time with your family. finaly you could lose your family. your happiness will decrease. this is the negative correlation.

In my opinion, I think that happiness have nothing to do with income. Happiness is a kind of feeling. It is the ability of our heart to feel thanks-giving of everything.
In modern society, it is hard to survive without income. However, high-income can only bring us higher quality of life. You can never buy a ture-heart friend, a really happy feeling from the bottom of heart.