Let X denote the number of customers arrives at a telephone booth in remote location per hour. Customer arrive at random and the average number of customers per hour is constant. Find the mean of X if it satisfies ()2=3()+4 . Let Y denote the number of customers arrive at a tea shop per hour which is located very near the telephone shop. Given X and Y are independent. If Y follows Poisson distribution with ()=7 then find the mean and variance of + also check whether + follows Poisson distribution. Find (+>1). Let be a random variable defined by =. Find the mean and variance of . Give your comment on the distribution of .