7.94 Japan’s rainy season starts in July and continues through August. From a random sample of 40 days in 2021, the mean temperature was around 26.3°C with a standard deviation of 1.6°C. Compute the 90% confidence interval estimate of Japan’s mean temperature in July and August.

7.95 Fifty patients at a hospital display symptoms of hyponatremia, which occurs when the concentration of sodium in the blood is abnormally low. A random sample of 10 patients’ blood sodium level (in mEq/L)

is taken, and the results are recorded as follows:

121 131 122 129 129 130 120 131 121 121

a. Find a 95% confidence interval for the population’s mean blood sodium level.

b. Without doing the calculations, state whether a 90% confidence interval for the population mean would be wider or narrower than the interval found in part a.