A real estate agent researches the factors that influence house prices in Brisbane. She collects data on recent sales and notes the size of each house in square metres. Suppose the house prices (and size in square metres) for the last ten sales are as follows.

Sales price ($’000) ............................................. Size (m²)
1200 ....................................................................... 280
653 ..........................................................................198
735 ..........................................................................220
825 ..........................................................................230
515 ..........................................................................150
635 ..........................................................................180
1350 ........................................................................318
690 ..........................................................................205

Develop a regression equation to predict the price of a house in Brisbane using the size in square metres. Compute residuals for this model. Obtain a graph of the residuals in the order of the x values. Comment on the shape of the residual graph.