In an experiment to study the regulation of insulin secretion, blood samples were obtained from seven dogs before and after electrical stimulation of the vagus nerve. The following values show, for each animal, the increase (after minus before) in the immunoreactive insulin concentration (µU/ml) in pancreatic venous plasma. 30 100 60 30 130 1,060 30

For these data, Student's t method yields the following 95% confidence interval for the population mean:
-145< m <556
Is Student's t method appropriate in this case? Why or why not?