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Introductory Statistics

MA207

Day 20 - Hypothesis Tests and Confidence Intervals�On Two Proportions

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Do Smoker Mothers Give Birth to a Higher Proportion of Low-Weight Babies?

This is the question that we have really wanted to answer with the baby_smoke.xlsx data set. Let’s first do a confidence interval.

  • Find the proportion of low-weight babies from smoker mothers.
  • Find the proportion of low-weight babies from non-smoker mothers.
  • Find:
  • The standard error for the confidence interval is:

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  • Build a 95% Confidence Interval for the difference

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Do Smoker Mothers Give Birth to a Higher Proportion of Low-Weight Babies?

Now for a hypothesis test:

  • Null Hypothesis:
  • Alternative Hypothesis:
  • Since we are assuming that the two populations are identical we need to build a confidence intervals based on the pooled proportion:
    • Find the proportion of the sample that had low-weight babies. Call this
    • The standard error for the hypothesis test is:�

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Ask a question

Ask a question of this data set that we would need a hypothesis test on two proportions to answer.