At a recent county fair, you observed that at one stand people's weight was forecasted, and were surprised by the accuracy (within a range). Thinking about how the person could have predicted your weight fairly accurately (despite the fact that she did not know about your "heavy bones"), you think about how this could have been accomplished. You remember that medical charts for children contain 5%, 25%, 50%, 75% and 95% lines for a weight/height relationship and decide to conduct an experiment with 110 of your peers. You collect the data and calculate the following sums:

n i=1 Yi = 17,375, n i=1 Xi = 7,665.5,

n i=1 y 2 i = 94,228.8, n i=1 x 2 i = 1,248.9,

n i=1 xi y i = 7,625.9 where the X is height measured in inches and Y is weight in pounds. (Small letters refer to deviations from means as in zi = Zi - Z.)

(a) Calculate the slope and intercept of the regression and interpret these.

(b) Use your derived formula in Question 2 to find the regression R2 and explain its meaning. What other factors can you think of that might have an influence on the weight of an individual?