a [30 points] An accountant reviewed a firm's billing for an entire year and computed an average bill of $125, with a standard deviation of $15. The firm's comptroller claims that a sample of 50 bills would have saved a lot of work and achieved the same result. (a) Is the sampling distribution of the sample mean approximately Normal? [10 points] (b) What is the sample mean and the standard deviation? [10 points] (c) Find the probability that the sample mean deviates from the population mean by no more than 3. [10 points]