WEBVTT

NOTE Wheeze: GEE, working correlations and robust errors: captions match the on-screen steps.

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Step 1 of 7. Ohio wheeze: 537 children seen every year from age 7 to 10, by mother's smoking.

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Step 2 of 7. Observed rates with 95% Wilson intervals; GEE fits with robust 95% bands.

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Step 3 of 7. Repeated visits are correlated: observed correlations against exchangeable α = 0.354.

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Step 4 of 7. Naive GLM vs GEE: the robust SE for smoking is 44% larger, so p goes from 0.028 to 0.136.

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Step 5 of 7. Switch the working correlation: exchangeable, independence, AR(1).

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Step 6 of 7. Model checks: the smoking effect barely moves, and QIC differs by under one unit.

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Step 7 of 7. One effect, several analyses: only the naive GLM's interval excludes an odds ratio of 1.