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Making Sense of Data: A Practical Guide to Exploratory Data Analysis and Data Mining by Glenn J. Myatt

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5.5 SUMMARY

Central Tendency

Mode: Most common value

Median: Middle value

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Variation

Range: high–low

Quartiles: Q1 (25%), Q2 (50%), Q3 (75%)

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Confidence Levels

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Hypothesis Test

Specify null (e.g. H0: μ = μ0) and alternative hypothesis (e.g. Ha: μ > μ0)

Select significance level (e.g. α = 0.05)

Compute test statistics (t- or z-)

Determine critical value for t or z using α/2 for two sided tests

Reject the null hypothesis if test statistic fall in the “reject H0” region

Comparing Groups

When comparing more than two groups, use:

Chi-square test for categorical data

One-way analysis of variance test for continuous.

Comparing Variables

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