A researcher estimates the following quadratic relationship between daily earnings (in dollars) and years of education:
earnings_hat = 10 + 5education + 1education^2
What is the estimated change in earnings associated with moving from 6 to 8 years of education?
A. $6 per day
B. $12 per day
C. $38 per day
D. Need more information.
Answer: C. $38 per day