2.97 and 2.98 Solutions

2.97 and 2.98 Solutions - b) The standard deviation for the...

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David Weiss ECON 306 Homework 2.97 a) The 10 th percentile of the data set is 0 . This means that 10 percent of the counties in Arkansas have 0 Superfund sites in them. b) The 95 th percentile of the data set is 21 . This means that 95 percent of the counties in Arkansas have 21 or less Superfund sites in them. c) The mean is 393/75 = 5.24. The standard deviation is 7.24. The z-score for an Arkansas county with 48 Superfund sites is z = (48 – 5.24)/7.24 = 5.91. d) Yes, 48 is an extreme number because the z-score is high. 2.98 a) The standard deviation for the students that took the blue exam says that 2/3 of the students scored between 38% and 68% on the graded problems.
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Unformatted text preview: b) The standard deviation for the students that took the red exam says that 2/3 of the students scored between 27% and 51%. c) The student has most likely taken the red exam . This is because the score of 20% is closer to the median of the students who took the red exam. Also, if you go two standard deviations away from the mean, which accounts for 95% of the data, you will see that the red exams lower extreme is 15% while the blue exams lower extreme is 23%. This makes it very unlikely for the student to have taken the blue exam....
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