More indicators For each of these potential predictor variables say whether they should be represented in a regression model by indicator variables. If so, then suggest what specific indicators should be used (that is, what values they would have).

a) In a regression to predict income, the age of respondents in a survey

b) In a regression to predict the square footage available for rent, whether a commercial building has an elevator or not

c) In a regression to predict annual medical expenses, whether a person was a child (in pediatric care), an adult, or a senior

(over 65 years old)