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14 Cards in this Set
- Front
- Back
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positive predictive value |
a/(a+b) horizontal |
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negative predictive value |
d/(d+c) horizontal |
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sensitivity |
a/(a+c) --> vertical or 1-false negative rate |
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specificity |
d/(d+b) --> vertical or 1-false positive rate |
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effect of high disease prevalence in pop on PPV, NPV |
PPV will inc, NPV will decrease |
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relative risk |
[a/(a+b)]/[c/(c+d)]
risk of developing disease in exposed group/risk in unexposed group (probability of having disease with exposure/probability of having disease without exposure) |
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relative risk reduction |
1-RR [(absolute risk control)-(absolute risk tx)]/absolute risk
control proportion of risk reduction attributable to intervention as compared to control |
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odds ratio |
AD/BC |
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attributable risk |
[a/a+b)] - [c/(c+d)] diff in risk between exposed & unexposed groups
=exposed with disease - disease with no exposure if given risk of disease for exposed group (X%) and risk of disease for unexposed group (Y%) then AR=X-Y |
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number needed to harm |
1/AR |
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absolute risk reduction |
[c/(c+d)] - [a/(a+b)] diff in risk attributable to intervention vs control
=risk of disease in control group - risk of disease in intervention group if given risk of disease with intervention (X%) and risk of disease without intervention (Y%) then ARR=X-Y |
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number needed to treat |
1/ARR |
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SEM (standard error of mean) |
= SD/square root of sample size |
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confidence interval |
mean +/- Z(SEM) 95% CI Z=2, 99% CI Z=2.5
reasons to NOT reject Ho: if 95% CI for mean includes zero, or for odds ratio or relative risk includes 1, or if the CI's between two groups overlap |
