Divide the below data into four brands according to the maximum number of copiers served (X). Brand 1 ranges from x=0.5 to X=2.5; band 2 ranges from x=2.5 to 4.5 and so forth. Determine the median value of X and the median value of Y in each of the bands and develop the band smooth by connection in the four pairs of medians by St lines on a scatter plots of the data. Does the band smooth suggest that the regression relation is linear? Discuss?

i: 1 2 3 ..... 43 44 45
Xi: 2 4 3 ..... 2 4 5
Yi: 20 60 46 ..... 27 61 77