Patho Equations

Question 1

Point Prevalence

Answer 1

of existing cases / population

Question 2

Incidence Risk

Answer 2

of new cases / # of healthy people at the beginning of time

Risk = d/n

Question 3

Incidence Rate

Answer 3

Rate = d/y

Question 4

Sensitivity

Answer 4

Sensitivity = TP/(TP + FN) = TP / total sick people

Question 5

Specificity

Answer 5

Specificity = TN/(TN + FP) = TN / total healthy people

Question 6

Positive Predictive Value

Answer 6

PPV = TP / (TP + FP) = TP / all positives

Question 7

Negative Predictive Value

Answer 7

NPV = TN / (TN + FN) = TN / all negatives