Samples of rainbow trout taken from the Spokane River were tested for lead and for zinc content, in milligrams per kilogram.
a. Suppose we consider performing a paired t test on the differences, lead minus zinc. Just by looking at the numbers, predict whether the t statistic will be very large in absolute value and negative, very close to zero, or very large in absolute value and positive; explain.
b. Based on your response to part (a), predict whether the P-value will be very small, not small at all, or borderline.
c. By hand or with software, carry out the paired test; first report the t statistic.
d. Report the P-value of the test.
e. Comment on whether or not your predictions in parts (a) and (b) were correct.