Suppose that in the town of Springfield, RI, the number of days per year with no measurable precipitation is approximately normally distributed with a mean of 85.1 days and a standard deviation of 7.5 days. Ms. Johnson, who lives on a farm just outside of Springfield, wonders if the mean number of days with no measurable precipitation on her farm is different from in town. Her grandfather maintained meticulous weather records. She obtains a simple random sample of eight years from her grandfather's records, and determines that the mean number of days with no measurable precipitation in those years was 82.3 days. She plans to conduct a one-sample ????z ‑test, assuming that the standard deviation of days with no measurable precipitation is the same at the farm as in town. Choose the appropriate null and alternative hypotheses for such a test.