1000 light bulbs with a mean life of 120 days are installed in a new factory and their length of life is normally distributed with a standard deviation of 30 days.
1000 light bulbs with a mean life of 120 days are installed in a new factory and their length of life
is normally distributed with a standard deviation of 30 days
ANS : TAKE X PWR 1 =1000
MEU = 120
SD = 30