1. You suspect that the relationship between humidity and PM2.5 concentration may be a quadratic relationship. Extend the model in Part 1 to allow for this relationship. Estimate this model and include your output.
2. Interpret the marginal effect of humidity when humidity is 30 percentage points.
When i do the derivative for Q2, is it 3.385341+ (2 x (-0.009183) x 0.3) = 3.3798 or 3.385341+ (2 x (-0.009183) x 30) = 2.834334
Do i multiply it by 0.3 or 30 in the equation?