A study indicates that 18- to 24- year olds spend a mean of 140 minutes watching video on their smartphones per month. Assume that the amount of time watching video on a smartphone per month is normally distributed and that the standard deviation is 15 minutes Complete parts (a) through (d) below. a. What is the probability that an 18- to 24-year old spends less than 120 minutes watching video on his or her smartphone per month? The probability that an 18- to 24-year-old spends less than 120 minutes watching video on his or her smartphone per month is JOB18 (Round to four decimal places as needed ) b. What is the probability that an 18-to 24-year-old spends between 120 and 150 minutes watching video on his or her smartphone per month? The probability that an 18-to 24-year-old spends between 120 and 150 minutes watching video on his or her smartphone per month is 0.6568 (Round to four decimal places as needed ) c. What is the probability that an 18- to 24-year-old spends more than 150 minutes watching video on his or her smartphone per month? The probability that an 18-to 24-year-old spends more than 150 minutes watching video on his or har smartphone per month is 0 2514 Round to four decimal places as needed ) d. Five percent of all 18- to 24-year-olds will spend less than how many minutes watching video on his or her smartphone per month? Five percent of all 18- to 24-year-olds will spend less than | | minutes watching video on his or her smartphone per month (Round to two decimal places as needed )