The lives of parts are often expressed as the number of cycles of operation that a specified percentage of a population will exceed before experiencing failure. The symbol L Page 38 is used to designate this definition of life. Thus, we can speak of L10 life as the number of cycles to failure exceeded by 90 percent of a population of parts. Given a normal distribution model, with a mean L= 122.9 of kilocycles and standard deviation of sL = 30.3 kilocycles, estimate the corresponding L10 life.