Removing metal from water. In the Electronic Journal of Biotechnology (Apr. 15, 2004), Egyptian scientists studied a new method for removing heavy metals from water. Metal solutions were prepared in glass vessels, and then biosorption was used to remove the metal ions. Two variables were measured for each test vessel: y = metal uptake (milligrams of metal per gram of biosorbent) and x = final concentration of metal in the solution (milligrams per liter).

a. Write a simple linear regression model relating y to x.

b. For one metal, a simple linear regression analysis yielded r2

= .92. Interpret this result.