Stat 312 Homework Problems - Week 10

The data are paired by test condition position on the

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Unformatted text preview: are paired by Test Condition (“position on the original cylinder”?) The scatterplot seem s to indicate that the pairing variable will not prove very useful. b. A 95% confidence interval is given by Normal High D=N-H n 15 15 15 mean 47.9 90.1 -42.2 s 3.93 1.96 4.34 B ox Plot of multiple variables Normal and High Strength Concrete Peak Stress 100 90 80 70 . A normal probability plot 60 50 of the differences indicates the validity of using the t distributi on. The huge distance of this 95% confidence interval from zero indicates that there is a big difference between the mean peak stress for the normal versus high stress mixes. 40 Normal High 43. The statistics are in the table. The standard error is 5.98. n mean s a. The normal probability plot does not exhibit noteworthy curvature, so there is no D=O-D 15 -38.6 23.2 reason to doubt that the data are not normal. b. The lower confidence bound uses t.05;14 = 1.761, and is given by -38.6 - 1.761(5.98) = -38.6 - 10.5 = -49.1. We are 95% confidence that the mean number of months between the onset of Cushing’s disease and its diagnosis is no greater than 49.1 months. c. In...
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This note was uploaded on 09/17/2012 for the course STAT 312 taught by Professor Chung during the Spring '04 term at University of Wisconsin.

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