$2.$ The following equations were estimated using the data in BWGHT$.$RAW:whitemaleparitycfacigsbwght $045\mathrm{.}034\mathrm{.}017.)$minlog$(00110\mathrm{.}0052\mathrm{.}65\mathrm{.}4)$log$(++++=$

$(\mathrm{.}38)(\mathrm{.}0010)(\mathrm{.}0085)(\mathrm{.}006)(\mathrm{.}011)(\mathrm{.}015)$

n $=1,388,$ R$2=0\mathrm{.}0472$whitemaleparitycfacigsbwght $055\mathrm{.}027\mathrm{.}016.)$minlog$(0093\mathrm{.}0044\mathrm{.}66\mathrm{.}4)$log$(++++=$

$(\mathrm{.}22)(\mathrm{.}0009)(\mathrm{.}0059)(\mathrm{.}006)(\mathrm{.}010)(\mathrm{.}013)$fatheducmotheduc $0032\mathrm{.}0030.+$

$(\mathrm{.}0030)(\mathrm{.}0026)$

n $=1,191$ R$2=0\mathrm{.}0493$

where bwght is the birth weight in pounds, cigs denote average number of cigarettes the

mother smoked per day during pregnancy, parity is the birth order of this child, faminc

denotes annual family income, motheduc denotes years of schooling for the mother, and

fatheduc is the number of years of schooling for the father. We have added a dummy

variable for whether the child is male and a dummy variable indicating whethe the child

is classified as white.

$2$

a$.$ In the first equation, interpret the coefficient on the variable cigs. In particular, what is

the effect of birth weight from smoking $10$ more cigarettes per day?

b$.$ How much more is a white child predicted to weight than a nonwhite child, holding the

other factors in the first equation fixed? Is the difference statistically significant?

c$.$ Comment on the estimated effect and statistical significance of motheduc.

d$.$ From the given information, why are you unable to compute the F statistic for joint

significance of motheduc and fatheduc? What would you have to do to compute the F

statistic?