It is assumed that the life span of the street lights on an avenue in Gatineau has a normal distribution a normal distribution with a mean of 80 months and a variance of 800 months². Hydro-Qubec selects 15 of these streetlights at random for a statistical study. 1. What is the probability that only 3 of them will last more than 9 years? 2. What is the probability that their average life span will not exceed one year and a half?