A business has six customer service telephone lines. Consider the random variable x = number of lines in use at a randomly selected time. Suppose that the probability distribution of x is as follows. x 0 1 2 3 4 5 6 p(x) 0.05 0.15 0.20 0.30 0.20 0.07 0.03 (a) Consider the following questions. (i) Calculate the mean value of x . Enter a number. x= (ii) Calculate the standard deviation of x . (Round your answer to four decimal places.) Enter a number. x= (b) What is the probability that the number of lines in use is farther than 3 standard deviations from the mean value