How would a statistician charged with measuring national product accounts distinguish pure price increases from productivity increases in the cell phone industry? Why might a statistician be asked to do this? Be as specific as possible about the method you would employ for a single product line. [Hint, a productivity increase on a fixed model of a cell phone would lower its cost of production. So that productivity would show up here in lowering prices. Thus for a productivity increase to raise the cost of a typically purchased cell phone, the quality of the typical phone must also increase. Think what this means for the estimate of inflation.]