let X be a raondom variable that represents the number of infants in a group of 2000 who die before reaching their first birthdays. In the US, the probability that a child dies during his or her first year of life is .0085. What is the probability that at most 5 infants out of 2000 die in their first year of life? Solution (a) What is the mean number of infants who would die in a group of this size? Since this is a binomial distribution the mean = n*p = 17 (b) What is the probability that at most five infants out of 2000 die in their first year of life? The conditions are sufficient to approximate this random variable with either a poisson or normal distribution. Poisson: P(X<=5) = P(X=0) +.