A population begins with a single individual. In each generation, each individual in the population dies with probability ½.or doubles with probability ½. Let X,, denote the number of individuals in...

A population begins with a single individual. In each generation, each individual in the population dies with probability ½.or doubles with probability ½. Let X,, denote the number of individuals in the population in the nth generation. Find the mean and variance of X,,.