Question

multiple choice. choose the one alternative that best completes the statement or answers the question. solve the problem. 1) the annual precipitation amounts in a certain mountain range are normally distributed with a mean of 109 inches, and a standard deviation of 10 inches. what is the probability that the mean annual precipitation during 25 randomly picked years will be less than 111.8 inches? a) 0.5808 b) 0.4192 c) 0.0808 d) 0.9192 2) the scores on a certain test are normally distributed with a mean score of 60 and a standard deviation of 5. what is the probability that a sample of 90 students will have a mean score of at least 60.527? a) 0.3174 b) 0.1587 c) 0.3413 d) 0.8413 3) in one region, the september energy consumption levels for single - family homes are found to be normally distributed with a mean of 1050 kwh and a standard deviation of 218 kwh. if 50 different homes are randomly selected, find the probability that their mean energy consumption level for september is greater than 1075 kwh. a) 0.4562 b) 0.0438 c) 0.2090 d) 0.2910 4) suppose that replacement times for washing machines are normally distributed with a mean of 9.3 years and a standard deviation of 1.1 years. find the probability that 70 randomly selected washing machines will have a mean replacement time less than 9.1 years. a) 0.0714 b) 0.4357 c) 0.4286 d) 0.0643 5) for women aged 18 - 24, systolic blood pressures (in mm hg) are normally distributed with a mean of 114.8 and a standard deviation of 13.1. if 23 women aged 18 - 24 are randomly selected, find the probability that their mean systolic blood pressure is between 119 and 122. a) 0.9341 b) 0.0833 c) 0.0577 d) 0.3343 6) a study of the amount of time it takes a mechanic to rebuild the transmission for a 2005 chevrolet cavalier shows that the mean is 8.4 hours and the standard deviation is 1.8 hours. if 40 mechanics are randomly selected, find the probability that their mean rebuild time exceeds 9.1 hours. a) 0.1046 b) 0.0069 c) 0.1285 d) 0.0046 7) a study of the amount of time it takes a mechanic to rebuild the transmission for a 2005 chevrolet cavalier shows that the mean is 8.4 hours and the standard deviation is 1.8 hours. if 40 mechanics are randomly selected, find the probability that their mean rebuild time exceeds 8.1 hours. a) 0.8457 b) 0.7285 c) 0.9146 d) 0.8531 8) a study of the amount of time it takes a mechanic to rebuild the transmission for a 2005 chevrolet cavalier shows that the mean is 8.4 hours and the standard deviation is 1.8 hours. if 40 mechanics are randomly selected, find the probability that their mean rebuild time is less than 8.9 hours. a) 0.9589 b) 0.9756 c) 0.9608 d) 0.4276

Explanation:

Answer:

(1) D. 0.9192
(2) A. 0.3174
(3) C. 0.2090
(4) D. 0.0643
(5) C. 0.0577
(6) A. 0.1046
(7) A. 0.8457
(8) B. 0.9756