Biostats Equations Flashcards
1
Q
positive likelihood ratio
A
sensitivity / (1 - specificity)
2
Q
negative likelihood ratio
A
(1 - sensitivity) / specificity
3
Q
odds ratio
A
(a/b) / (c/d)
4
Q
relative risk
A
a/(a+b) / c/(c+d)
5
Q
relative risk reduction
A
1 - RR
6
Q
attributable risk
A
[a/(a+b)] - [c/(c+d)]
7
Q
absolute risk reduction
A
c/(c+d) - a/(a+b)
8
Q
number needed to treat
A
1/ARR
9
Q
number needed to harm
A
1/AR
10
Q
incidence
A
new cases / # people at risk
11
Q
prevalence
A
existing cases / # total people in population
12
Q
power
A
1 - beta
