Question: Archaeopteryx is an extinct beast having feathers like a bird but teeth and a long bony tail like a reptile. Only a few fossil specimens are known. Because these specimens differ greatly in size, some scientists think they belong to different species. If the specimens belong to the same species and differ in size because some are younger than others, there should be a positive linear relationship between the lengths of a pair of bones from all individuals. An outlier from this relationship would suggest a different species. Here are data on the lengths in centimeters of the femur and the humerus from five specimens:

a. Construct a scatter plot of femur and humerus length and attach the graph to the back of this exam. Do you think that all five specimens could have come from the same species?

b. Find the correlation coefficient. How does it support your interpretation?

c. Does it matter whether you use femur or humerus length for the x axis? Explain why.