So, to be a linear relationship....the difference between the two consecutive "x" values and the difference between the two consecutive "y" values must be same.
In this case, if we look at the x values , 4 - 3 = 1 3 - 2 = 1 2 - 1 = 1 they are all the same, <u>BUT,</u><u><em /></u> if we look at the y values, 11.5 - 8.5 = 3 8.5 - 6.5 = 2 6.5 - 4.5 = 2 Here, the differences between the "y" values are all not the same.
<em><u>SO, the relationship is not linear.</u></em>