Physical Sciences
The Palmer Drought Severity Index (PDSI) is a measure of prolonged abnormal dryness or wetness. It indicates general conditions and is not affected by local variations. An index value of -4 indicates extreme drought, and +4 represents very wet conditions. A random sample of the PDSI for selected regions in the Eastern United States for the week ending July 6, 2013, was obtained, and the data are given in the following table.
a. Is there any evidence to suggest the true mean PDSI is different from 0? Assume the underlying distribution is normal and use a = 0.01. Find bounds on the p value associated with this test.
b. Explain your conclusion in part (a) in terms of farming conditions and reservoir levels.