44. 45. 46. 47. Assembling 6'in Phones The times taken by workers to assemble a certain kind of cell phone are normally dis tributed with mean 18. 5 minutes and standard deviation 3.1 minutes. Find the probability that one such phone will require less than 12. 8 minutes in assembly Finding Bland Clotting Times The mean clotting time of blood is 7.47 sec. with a standard deviation of 3.6 see. What is the probability that an individual's blood-clotting time will be less than 7 sec or greater than 8 sec? Sizes of Fish The average length of the fish caught in Vernal Lake is 1.0.6 in., with a standard deviation of 3.2 in. Find the probability that a fish caught there will be longer than 16 in. Size Grading of Eggs To be graded extra large, an egg must weigh at least 2.2 oz. If the average weight for an egg is 1.5 oz. with a standard deviation of 0.4 oz, how many of five dozen randomly chosen eggs would you expect to be extra large? Distribution of Student Grades Professor Cheng teaches a marketing course. He uses the following grading system. Grade Score in Class Greater than i -t- 1.53 3:" + 0.55 to E + 1.53 f - 0.55 to E + 0.55 f m 1.53 to if 0.55 Below if 1.55 \"HUGE