Answer Happy

5. (Normal Distribution). The Quality Control Department of a certain factory discovered that the lifespan of a light bulb produced by the factory has a normal distribution with x = 2100 hours and o = 80 hours. What is the probability that a bulb will last: (i) between 2100 and 2850 hours? (ii) less than 1985 hours? Please give a complete solution to the problem. † As was discussed during the lectures on similar occasions, this in fact means that the probabilities Pla <L<b) related to the random variable, say L in question are well approximated by the corresponding probabilities Pla <L' <b) related to a random variable L' ~ N(1,0%) having a normal distribution with parameters 41 and 52. A similar clause applies to the formulation of the next problem.