Name:________________________________
Many wildlife populations are monitored by taking Length Weight
aerial photographs. Information about the number (inches) (pounds)
of animals and their whereabouts is important to
58
28
the effort of protecting certain species and to
61
44
ensure the safety of surrounding human
63
33
populations. In addition, it is sometimes possible to
68
39
monitor from aerial photographs or photographs
69
36
from a boat. An alligator’s weight is more
72
38
difficult to determine and useful to have when
72
61
making decisions about the alligator population in
74
54
particular areas.
74
51
In the example at right, datal of the length (in
76
42
inches) and weight (in pounds) of alligators
78
57
captured in central Florida are given. Your task is
82
80
to develop a model from which the weight of an
85
84
alligator can be predicted from its length.
86
83
86
80
86
90
88
70
89
84
90
106
90
102
94
110
a. Sketch and comment on a scatterplot of the
94
130
data with its least squares regression line.
114
197
b. Sketch and interpret the residual plot for the
128
366
linear model.
147
640
c. Sketch and comment on a scatterplot of
ln(weight) vs. length with its least squares line.
d. Sketch and interpret the residual plot for the exponential model.
e. Sketch and comment on a scatterplot of ln(weight) vs. ln(length)
with its least squares line.
f. Sketch and interpret the residual plot for the power model.
g. Which of the 3 models is best? Explain.
h. Using all three models, predict the weight for a 160 inch long
alligator. Do you have confidence in any of the predictions?
Name:__________________
g)
a.
b.
c.
d.
e.
f.
h) Legend:
x=__________________ y=______________________
First LSRL:
Prediction:
Exponential transformation, LSRL:
Prediction:
Power transformation, LSRL:
Prediction:
i)Do you have confidence in any of these predictions? Explain your answer.