The New York Times study of homes reported average house size in 2001 to be 2,428 square feet, compared with an average of 2,150 square feet in 1987. Suppose a study of homes over the years recorded the year from 1987 to the present, as well as the size of the house in square feet, to see if average house size increased steadily over time. Tell whether the variables are categorical or quantitative. Also, tell which is the role of explanatory variable and which is the response variable.