Paired sample sign test on equality of population medians
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Paired&-sample sign test on the equality of population medians
This is a non&-parametric test based on ordinal level data. The source of the data are a set of paired values from two samples. The hypothesis is that the population median of both sets of data are the same. There does exist a non&-parametric test that uses the fact that the data can be ranked. It is called the paired&-sample Wilcoxon signed rank test on equality of population medians. However, the paired&-sample sign test is a ''simpler'' test that first reduces the data to nominal level. Example&: In the past suspects of drink driving were required to walk on a white line. Ten volunteers were asked to walk a white line before and after drinking two pints of a Manchester ale. The distances travelled before wobbling off were measured to the nearest metre, and the following results were obtained. [Table goes here &- download the original to see it.] Test at the 5% significance level whether getting drunk on Manchester ale makes a difference to your ability to walk straight. H0&:there is no difference in the medians. H1 median value after drinking ale is less than median value before drinking ale. We proceed by considering the sign of the difference. [Table goes here &- download the original to see it.] Let X = number of negative signs. We delete the 0 score from the test. Then X ~ B(9, 0.5) [Equation goes here &- download the original to see it.] [Equation goes here &- download the original to see it.] [Equation goes here &- download the original to see it.]
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Paired sample sign test on equality of population medians
1 Paired&-sample sign test on the equality of population medians
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