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Nonparametric Tests with Ordinal Data

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## Nonparametric Tests with Ordinal Data

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**Nonparametric Tests with Ordinal Data**Chapter 18**The sample data for the ordinal variable,**accomplishment-related national pride, are skewed. This indicates the possibility that the underlying population distribution is skewed.**When both variables are ordinal**Quantifies association Calculating Spearman’s correlation Convert interval observations to rank-ordered observations Spearman Rank-Order Correlation Coefficient**The Wilcoxon Signed-Rank Test**• A test for matched pairs is a nonparametric hypothesis test used when there are two groups, a within-groups design, and an ordinal dependent variable.**Steps for the Wilcoxon Signed-Rank Test**• Step 1. Identify assumptions • Step 2. State null and research hypotheses • Step 3. Determine characteristics of comparison distribution • Step 4. Determine critical values • Step 5. Calculate the statistic • Step 6. Make a decision**Mann-Whitney U test**• Nonparametric hypothesis test with two groups, a between-groups design, and an ordinal DV**Steps for the M-W U**• Step 1. Identify assumptions • Step 2. State research and null hypotheses • Step 3. Determine characteristics of comparison distribution • Step 4. Determine critical values • Step 5. Calculate the statistic • Step 6. Make a decision**Kruskal–Wallis H Test**• A nonparametric hypothesis test used for more than two groups a between-groups design, and an ordinal dependent variable.**Steps for the K-W H Test**• Step 1. Identify assumptions • Step 2. State research and null hypotheses • Step 3. Determine characteristics of comparison distribution • Step 4. Determine critical values • Step 5. Calculate the statistic • Step 6. Make a decision**Bootstrapping**• A statistical process in which the original sample data are used to represent the entire population. • We repeatedly take samples from the original sample data to form a confidence interval.