Refer to the alligator data in Table D.11 of the Data Bank. Using the data on x3 and x4 for male and female alligators from Lake Apopka:
(a) Make a scatter diagram of the pairs of concentrations for the male alligators. Calculate the sample correlation coefficient.
(b) Create a multiple scatter diagram by adding, on the same plot, the pairs of concentrations for the female alligators. Use a different symbol for females. Calculate the sample correlation coefficient for this latter group.
(c) Comment on any major differences between the male and female alligators.