Suppose you estimate the following fitted model:

birthweight= ₀ + ₁cigs + ₂ faminc + epsilon

where birthweight is child birth weight in ounces, cigs is the average daily number of cigarettes smoked per day by the mother during pregnancy, and faminc is family income measured in dollars. ₀ is an estimate of

Group of answer choices

how many cigarettes a day it takes to lower birth weight by 1 ounce, on average

how many ounces an extra cigarette a day lowers birth weight, on average.

how many ounces the average baby weighs, when cigs=0 and faminc=0.

none of the above.