medical expenditure in USD
indicates female patients
age in years
squared age
cubed age
age power 4
age power 5
logarithm of annual income
annual income in USD
squared annual income
cubed annual income
annual income power 4
annual income power 5
indicates that the patient has private health insurance
indicates that the patient has diabetes
indicates that the patient has hypertension
indicates that the patient is obese
indicates that the patient has high cholesterol
indicates that the patient is a smoker
indicates that the patient drinks at least one alcoholic beverage per day
indicates that the patient is sedentary
square root of annual income