Question 1.
A tire manufacturer believes that the treadlife of its snow tires can be described by a Normal model with a mean of 32,000 miles and standard deviation of 2500 miles.
If you buy one of these tires, would it be reasonable for you to hope it will last 40,000 miles? Approximately, what fraction of these tires can be expected to last less than 30,000 miles?
If someone can help me with understanding this question, I really appreciate it.