Hello, I am unsure if question 17a is correct and having trouble with my code for 17b (will not run) not sure if the codes are correct?

The databreastfeeding.csv

variables measured on baby and mother.

Sex: Infant sex

MomAge: Mom age at birth of infant (years)

MomEdu: Mom years of education

MomWtPrePg: Mom weight pre-pregnancy (pounds)

PregWtGain: Mom weight gained during pregnancy (pounds)

MomWtBirth: Mom weight at birth of infant (pounds)

InfantWtBirth: Infant Birth Weight (pounds)

Breastfed: Whether the mother breastfed for at least a week

BreastfeedDuration: Duration of breastfeeding (weeks), truncated at 50 weeks

AgeBeganSolids: Age introduced solid foods (weeks)

InfantWt6m: Infant weight at 6 months (pounds)

InfantWtGain: Infant weight at 6 months - infant birth weight

ToddlerWt18m: Toddler weight at 18 months (pounds)

ToddlerWtGain: Toddler weight at 18 months - infant birth weight

MomWt18m: Mom weight (pounds) at infant age 18 Months

MomWtLoss: Mom weight loss from infant birth to 18 months (pounds)