Sep19 Onwards - Highly skewed distributions Assumptions...

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September 26, 11 21:37 Chapter 5
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September 19, 11 21:37 Chapter 4. Alternatives to the t-Tools Case Study1: O-Ring Failures Was 4 observations and they did wrong statistic. ˆ Normality (drastically violated)  Log transformation ( will not help this data ) Can’t use Rank Sum Test( it doesn’t work well when we have lots of ties ) Case Study 2: Cognitive Load Pictures vs. text.  Sydney Australia Students were not exposed to geometry, but had enough math experience.  Randomized Experiment Students not randomly selected Was censored data
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Unformatted text preview: Highly skewed distributions Assumptions Violated Data are censored Normality Rank-Sum Test Other names Wilcoxon Rank-sum test (Frank Wilcoxon, a chemist not a statistician) Mann-Whitney U Nonparametric or distribution free tool. No specific distribution assumptions Tests the null hypothesis of identical population medians Assumption: Performs nearly as well as the two-sample t-test when the data are normal and considerably better when there are extreme outliers. September 19, 11 21:37 21:37...
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This note was uploaded on 11/30/2011 for the course STAT 380 taught by Professor Stevens during the Spring '11 term at Brigham Young University, Hawaii.

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Sep19 Onwards - Highly skewed distributions Assumptions...

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