10. It is known that the length of a certain steel rod is normally distributed with a mean of 100 cm and a standard devi

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10 It Is Known That The Length Of A Certain Steel Rod Is Normally Distributed With A Mean Of 100 Cm And A Standard Devi 1 (19.79 KiB) Viewed 39 times

10. It is known that the length of a certain steel rod is normally distributed with a mean of 100 cm and a standard deviation of 0.45 cm a. What is the probability that a randomly selected steel rod has a length less than 99.2 cm? b. What is the probability that a randomly selected steel rod has a length between 99.8 and 100.3 cm? c. Suppose the manufacturer wants to accept 90% of all rods manufactured Determine the length of rods that make up the middle 90% of all steel rods manufactured 11. According to MLB rules, the ball must weigh between 5 and 5.25 ounces. A factory produces baseballs whose weights are normally distributed, with a mean of 5.11 ounces and standard deviation of 0.062 ounces (a) Draw a normal curve with the parameters labeled (b) What proportion of the baseballs produces by this factory are too heavy for Major League Baseball? (c) What proportion of baseballs produced by thus factory can be used in the MLB? (d) If 8000 baseballs are ordered, how many baseballs should be manufactured knowing that some will need to be discarded? 12. Suppose the talk time of the Apple iPhone is approximately normally distributed with a mean of 7 hours and a standard deviation of 0.8 hours. a) What proportion of fully charged Phones will last at least 6 hours? b) Would it be unusual the phone to last more than 9 hours? Explain.