Smartphones: A poll agency reports that 86% of teenagers aged 12 - 17 own smartphones. A random sample of 270 Espanol teenagers is drawn. Round your answers to at least four decimal places as needed. Part: 0 / 6 Part 1 of 6 (a) Find the mean un X The mean um is Part: 1 / 6 Part 2 of 6 (b) Find the standard deviation on. X The standard deviation on is . Part: 2 / 6 Part 3 of 6 (c) Find the probability that more than 90% of the sampled teenagers own a smartphone. X 5 The probability that more than 90% of the sampled teenagers own a smartphone is. Part: 3 / 6 Part 4 of 6 (d) Find the probability that the proportion of the sampled teenagers who own a smartphone is between 0.83 and 0.90 . X The probability that the proportion of the sampled teenagers who own a smartphone is between 0.83 and 0.90 is Part: 4 / 6 Part 5 of 6 (e) Find the probability that less than 90% of sampled teenagers own smartphones. x s The probability that less than 90% of sampled teenagers own smartphones is