A real estate brokerage gathered the following information relating the selling prices of three-bedroom homes in a particular neighborhood to the sizes of these homes. (The square footage data are in units of 1000 square feet, whereas the selling price data are in units of $1000.)

Square footage

Selling price

2.3

240

1.8

212

2.6

253

3.0

280

2.4

248

2.3

232

2.7

260

(a) Plot the data in a scatter diagram.

(b) Determine the estimated regression line.

(c) What percentage of the selling price is explained by the square footage?

(d) A house of size 2600 square feet has just come on the market. Determine an interval in which, with 95 percent confidence, the selling price of this house will lie.