Normal Distribution Practice 7 Name __________________________________________
1. The mean life of a tire is 30,000 km. The standard deviation is 2000 km.
a) What percent of the tires will have a life that exceeds 25,000 km?
b) If a company purchased 2000 tires, how many tires would you expect to last more than 27 400 km?
2. The shelf life of a particular cheese is normally distributed with a mean of 12 days and a standard deviation of 3 days.
a) About what percent of the cheese last between 10 and 15 days?
b) About what percent of the cheese last between 13 and 16 days?
c) The oldest 10% of cheese are put on sale. These cheeses will be older than what age?
d) From a random selection of 60 cheeses, how many would you expect to be over a week old?
