(a) The probability of being a smoker among a group of cases with lung cancer is 0.6. Calculate the probability that in a group of 5 cases, you have at least one smoker. (b) What are the expected value and variance of the number of smokers? The number of babies born in a day at a hospital's maternity wing follows a Poisson distribution with a mean of 4 in a day. Calculate the probability that five babies are born during a particular day in this maternity wing. (c) (d) A survey of 500 adults showed that 240 of them drank alcohol daily. Calculate standard error for the adult population that drink alcohol daily and also construct the 95% confidence level.