Biostatistics

Recreate choosing a statistical test table

Recreate measures of effect table

Recall the calculation for Relative Risk (RR)

Relative Risk (RR) = [A/(A+B)] / [C/(C+D)]

Recall the calculation for Odds Ratio (OR)

Odds Ratio (OR) = (A/B) / (C/D)

Recall the calculation for Relative Risk Reduction (RRR)

Relative Risk Reduction (RRR) = 1-RR (x100 to get a percentage)

Recall the calculation for Absolute Risk Reduction (ARR)

Absolute Risk Reduction (ARR) = [A/(A+B)] - [C/(C+D)]

Recall the calculation for Number Needed to Treat (NNT)

Number Needed to Treat (NNT) = 1 / ARR

Explain the meaning behind Hazard Ratio (HR) values

When HR = 1 → no difference between groups

When HR < 1 → lower risk of event in treatment group

When HR > 1 → higher risk of event in treatment group

HR of 0.7 = 30% relative reduction in hazard

Recreate the table for test characteristics

Recall the Sensitivity calculation and definition

SnNout → Sensitive tests when Negative rule OUT disease

Sensitivity = A / (A+C)

The ability to detect when the disease is present

Recall the Specificity calculation and definition

SpPin → Specific tests when positive rule IN disease

Specificity = D / (B+D)

The ability to rule out the disease when it’s absent

Recall the Positive Predictive Value calculation and definition

Positive Predictive Value = A / (A+B)

Those that tested positive and have the disease

Recall the Negative Predictive Value calculation and definition

Negative Predictive Value = D / (C+D)

Those who tested negative and do not have the disease

Recall the Efficiency calculation and definition

Efficiency = A+D/A+B+C+D

Percentage of time the test is correct