Stat 312 Homework Problems - Week 10

# This shows how valuable degrees of free dom are when

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Unformatted text preview: how valuable degrees of free dom are when the sample sizes are small. Section 9.3 37. Differences of the form (Outdoor – Indoor) hexavalent chromium were calculated, giving rise to the data in the table. The data are paired by location, so a paired analysis is the appropriate approach. a. The confidence interval for D = O – I is given by Indoor Outdoor D=O-I n 33 33 33 mean .231 .655 .424 s .128 .380 .387 . W e are 95% confident that the mean outdoor hexavalent chromium exceeds the mean indoor value by .287 to .561nanograms/cm 3. b. The prediction error for a newly observed difference (outdoor-indoor) in hexavalent chromium is . The 95% prediction interval for a newly observed difference of outdoor minus indoor hexavalent chromium is given by . W e are 95% confident that a newly observed house would have a difference of outdoor minus indoo r chromium between -.376 and 1.224 nanograms/cm3. 38. The sample statistics for peak stress are given in the table. a. The box plot is given at right. Peak stress has a mild positive skew for the normal strength mix. Neither box plot indicates strong non-normality. It’s pretty clear already what the answer to part (b) will be! The data...
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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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