Statistics Flashcards
Sensitivity formula
Sn = TP / (TP + FN)
Specificity formula
Sp = TN / (FP + TN)
Positive Predictive Value Formula
PPV = TP / (TP + FP)
Negative Predictive Value Formula
NPV = TN / (TN + FN)
What statistical values increase as prevalence increases?
PPV and NPV
Prevalence formula
Prev = (TP + FN) / (TP + FP + TN + FN)
Positive Likelihood Ratio formula
LR+ = Sn / (1 - Sp)
Negative Likelihood Ratio formula
LR- = (1 - Sn) / Sp
Absolute risk formula
ARR = EER/Total in experimental group
EER = Experimental event rate
A / (A+C)
Relative Risk Formula
RR = EER/ CER
EER = Experimental event rate
CER = control event rate
A / B
Absolute risk reduction formula
ARR = | ERR - CER |
|A-B|
Relative Risk Reduction formula
RRR = ARR/CER
|A-B| / B
Number needed to treat formula
NNT = 1 / ARR
Number needed to harm formula
NNH = 1 / ARI
Absolute Risk Increase formula
ARI = (AR for experimental group) - (AR for control group)
A/(A+B+C+D) - B/(A+B+C+D)
