1. A certain city divides naturally into ten district neighborhoods. How might a real estate appraiser select a sample of single-family homes that could be used as a basis for developing an equation to predict appraised value from characteristics such as age, size, number of bathrooms, distance to the nearest school, and so on?
2. The amount of ow through a solenoid valve in an automobile s pollution-control system is an impor- tant characteristic. An experiment was carried out to study how ow rate depended on three factors: armature length, spring load, and bobbin depth. Two different levels (low and high) of each factor were chosen, and a single observation on ow was made for each combination of levels.
a. The resulting data set consisted of how many observations?
b. Does this study involve sampling an existing population or a conceptual population?