Unit 7!

1) Over the past decade, there has been a strong positive correlation between teacher salaries and prescription drug cost.

(a) Do you think paying teachers more causes prescription drugs to cost more? Explain.

(b) What lurking variable might be causing the increase in one or both of the variables? Explain.

2) When we use a least-squares line to predict y values forx values beyond the range of x valuesfound in the data, are we extrapolating or interpolating? Are there any concerns about such predictions?