Question 3: (8 marks) A research collects the following data to determine whether there is

a linear relationship between the age of the copy machine and its monthly maintenance cost.

We have the following data

Machine Age x (years) Monthly cost y

A 1 62

B 2 78

C 3 70

D 4 90

E 4 93

F 6 103

You are given the following summary statistics:

sx = 1.75, sy = 15.38, x = 3.33, y = 82.67, and r = 0.93.

a. (3 marks) Give the equation of the least squares regression line for predicting the month

cost based the age of the machine.

b. (3 marks) When x increases by 1 standard deviation of x, by how much does y increase?

c. (2 marks) Give the residual for the 1st data point.