10(-9X8+1,450,395X-50-1.304)

The human resources manager at a company records the length, in hours, of one shift at work, x. he creates the probability distribution below. what is the probability that a worker chosen at random works at least 8 hours? 0.62 0.78 0.84 0.96

How to square the standard deviation? how do you get the bottom number so you can actually square it? for instance, 22/6 squared is 1.91, where did they get the 6 from?

Is of ac? ! a. 12 b. 24 c. 60 d. 30