Problem #1 Suppose that a radio mechanic has 100 radio batteries whose lifetimes are independent exponential random variables with mean 5 weeks.

Problem #1

Suppose that a radio mechanic has 100 radio batteries whose lifetimes are independent exponential random variables with mean 5 weeks. If the batteries are used in a radio one a time, with a failed battery being replaced immediately by a new battery, approximate the probability that there is still a working battery in the radio after 525 weeks.

Hint: Consult the table of values for the standard normal distribution in your textbook, or at the Wikipedia link: https://en.wikipedia.org/wiki/ Standard_normal_table

Problem #2