They say money can’t buy happiness. Of course, they’re wrong. Research by economist David Clingingsmith at the Weatherhead School of Management shows that household income is positively related to emotional well-being and a person’s evaluation of their own quality of life.
For people who earn less than $200,000 a year, getting a pay rise improves their emotional wellbeing.
Above $200,000 the effects tail off.

Based on the research reported in the news clip,

a. How does an increase in income for people who earn less than $200,000 a year influence total utility?

b. How does an increase in income for people who earn less than $200,000 a year influence marginal utility?