Alliyah EvangelistaEpidemiology, Chp. 9 - Statisitical Measures of Effect
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What is a null hypothesis?
A statement where there is no difference between comparison groups. You can only fail to reject or reject the null hypothesis.
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What do larger sample sizes do?
- increase study precision
- statistical power
- generalizability of results
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What is statistical power?
The ability of a study to demonstrate the existence of an association.
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What factors determine statistical power?
1. frequency of condition
2. magnitude of effect
3. study design (meta-analysis has the most statistical power, hierarchy)
4. sample size
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___ sample sizes may lead to clinically unimportant yet statistically significant effects. ___ vice versa.
Large sample sizes may lead to clinically unimportant yet statistically significant effects. Small sample sizes vice versa.
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What does a multivariate analysis allow for?
To analyze multiple variables at the same time and to calculate measures of association -- odds ratios, risk ratios.
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If you randomize, do you need to control for cofounders?
No.
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Table 1 in data analysis shows what?
Shows the baseline characteristics of the study sample (ex. sex, age).
