Full-time college students report spending a mean of 23 hours per week on academic activities, both inside and outside the classroom. assume the standard deviation of time spent on academic activities is 6 hours complete parts (a) through (d) below. a. if you select a random sample of 16 full-time college students, what is the probability that the mean time spent on academic activities is at least 21 hours per week? 0.9088(round to four decimal places as needed.) b. if you select a random sample of 16 full-time college students, there is an 88% chance that the sample mean is less than how many hours per week? 24.77 (round to two decimal places as needed.) c. what assumption must you make in order to solve (a) and (b)?