6. [Revisiting question 4] Suppose again that amount of time full-time employees spend working on a workday is normally distributed with ,u = 525 minutes and a = 25 minutes. Determine the probability that a random sample of 10 full-time employees worked . . . a. . . . a mean of 9 hours or more [9 hours 540 minutes]. (5 pts] b. . . . a mean of 8 hours or less [8 hours = 480 minutes]. [5 pts] c. What do your solutions show you about the variability of sample means [Question 6] compared to individual observations [Question 4)? [2 points)