# A researcher wishes to estimate the body weight of wild elephants. 
# He measured the body weight of 13 captured elephants of different sizes as well 
# as a number of predictor variables, such as leg length, trunk length, etc. 
# Through stepwise regression, he found that the inter-leg distance (shown in figiure)
# is the best predictor of body weight.
# L: inter-leg distance
# W: Weight
L     W
0.31  1.657
0.43  2.500
0.52  4.680
0.59  7.075
0.70  10.070
0.83  11.988
0.89  14.836
1.12  18.318
1.13  23.496
1.19  27.897
1.25  36.796
1.41  44.611
1.50  51.183