Question

13.According to a report by the U.S. Fish and Wildlife Service, the mean length of six-year-old rainbow trout in the Arolik River in Alaska is 481 millimeters with a standard deviation of 41 millimeters. Assume these lengths are normally distributed.

a. What proportion of six-year-old rainbow trout are less than 450 millimeters long?

b. What proportion of six-year-old rainbow trout are between 400 and 500 millimeter long?

c. Is it unusual for a six-year-old rainbow trout to be less than 400 millimeters long? 1

4.According to the U.S. Energy Information Administration, the mean monthly household electric bill in the United States is $99.70. Assume the amounts are normally distributed with standard deviation $20.00.

a. What proportion of bills are greater than $130?

b. What proportion of bills are between $85 and $140?

Answer 1