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# example_sign - H0 number of mother ranks higher is the same...

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Stat 2225 Handout Examples of Sign Test Q17.54 on p.584. Hypothesis Tests for Mother-Child Sample mean = 0.26 Sample median = 0.0 sign test --------- Null hypothesis: median = 0.0 Alternative: greater than Number of values below hypothesized median: 5 Number of values above hypothesized median: 15 Large sample test statistic = 2.01246 (continuity correction applied) P-Value = 0.0220855 Do not reject the null hypothesis for alpha = 0.01. Step 0: Ordinal data types (ranking of pain); 2 matched sample (mother and child) Æ use sign test. Define mother ranks higher (feels more pain) than her child as + and mother ranks lower than her child as -, the pair will be dropped when the rankings are the same. m = 50. Step 1:
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Unformatted text preview: H0: number of mother ranks higher is the same as number of mother ranks lower. Ha: number of mother ranks higher is higher than mother ranks lower. Step 2: T = T + = 15. When n = 20, one-tailed with α = 0.01 can’t be found from table. Therefore, use normal approximation. E(T) = (20)(0.5) = 10 and V(T) = (20)(0.5)(0.5) = 5 TS = (15 – 10)/ 5 = 2.24. It has approx. standard normal distribution. Step 3: p-value = P(Z > 2.24) = 0.5 – 0.4875 = 0.0125. Since p-value < , we reject H0 and conclude that we have enough statistical evidence to infer that children feel less pain than adults do. Note: the calculate p-value is different from the one obtained from SGP output. Can you explain why? Page 1 of 1...
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