1) The alkalinity level of water specimens collected from the Han River in Seoul, Korea, has a mean of 50 milligrams per liter and a standard deviation of 3.2 milligrams per liter. Assume the distribution of alkalinity levels is approximately normal and find the the probability that a water specimen collected from the river has a alkalinity level:
a) exceeding 45 milligrams per liter
b) below 55 milligrams per liter
c) between 51 and 52 milligrams per liter
d) what is the 35th percentile value for the alkalinity level?
e) what is the 80th percentile value for the alkalinity level?.
2) You are measuring the heights of all the silver maples on campus, but you are unsure of the distribution of these tree heights. Your sample mean is 38.2 feet with a sample standard deviation of 3.8 feet. Using Chebyshev's theorem, calculate the percentage of tree heights between 32.5 feet and 43.9 feet tall.