The number of defect lamps found in every house has a Poisson distribution with mean 3.
a) Find the probability that for 7 particular houses, no defect lamps were found in 2 houses.
b) Find the probability that for 120 particular houses, at least 2 defect lamps were found in less than 70 houses
a) Find the probability that for 7 particular houses, no defect lamps were found in 2 houses.
b) Find the probability that for 120 particular houses, at least 2 defect lamps were found in less than 70 houses
