Ninth-grade students at the Webb Schools go on a backpacking trip each fall. Students are divided into hiking groups of size 8 by selecting names from a hat. Before leaving, students and their backpacks are weighed. The data here are from one hiking group. 1. Calculate the equation of the least-squares regression line.

2. Use the least squares regression line to calculate the residual for 165 body weight. Interpret the residual.

3. What does the residual plot indicate about the appropriateness of the linear model? Explain your answer.