An Experiment Was Performed on a Certain Metal to Determine $\hat { y }$

An experiment was performed on a certain metal to determine if the strength,in g/cm²,was a function of heating time,in minutes.The least-squares regression line was found to be $\hat { y }$
= 1 + 1x.What is the predicted value strength when the metal is heated for 4 minutes?

A) 1 g/cm²
B) 2 g/cm²
C) 3 g/cm²
D) 4 g/cm²
E) 5 g/cm²