# Question 15 of 20 50 50 points the area under the

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Question 15 of 20 5.0/ 5.0 Points The area under the standard normal curve between 1 and 2 is equal to 0.1359. Scores on a particular aptitude test are normally distributed with a mean of 100 and a standard deviation of 10. Which of the following are equal to 13.59%? a) The percentage of scores between 120 and 130
b) The percentage of scores between 110 and 120 c) The percentage of scores between 80 and 90 d) The percentage of scores between 90 and 120 A. b B. b, c C. d D. a, b Question 16 of 20 5.0/ 5.0 Points The lifetimes of projector bulbs of a particular type are normally distributed with a mean of 470 hours and a standard deviation of 15 hours. What percentage of the bulbs has lifetimes that lie within 2 standard deviations of the mean on either side? Apply the 68-95-99.7 rule to this question.
A. 68% B. 99.7% C. 95% D. 100% Question 17 of 20 5.0/ 5.0 Points Decide which of the described variables likely have a normal or near-normal distribution.
C. c D. None Question 18 of 20 5.0/ 5.0 Points The scores on a certain test are normally distributed with a mean score of 58 and a standard deviation of 4. What is the likelihood that a sample of 90 students will have a mean score of at least 58.4216?
Question 19 of 20 5.0/ 5.0 Points The systolic blood pressures of the patients at a hospital are normally distributed with a mean of 136 mm Hg and a standard deviation of 12 mm Hg. Find the two blood pressures having these properties: the mean is midway between them and 76.98% of all blood pressures are between them. A. 121.6, 152.4 B. 121.6, 150.4 C. 123.6, 150.4 D. 122.6, 148.4
Question 20 of 20 5.0/ 5.0 Points The diameters of bolts produced by a certain machine are normally distributed with a mean of 0.25 inches and a standard deviation of 0.01 inches. What percentage of bolts will have a diameter greater than 0.24 inches?
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