Statistics

Question 1

Sensitivity formula?

Answer 1

TP/(TP+FN) [TP/# of people with disease]

Question 2

Specificity formula?

Answer 2

TN/(TN+FP) [TN/# people without disease]

Question 3

PPV formula?

Answer 3

TP/(TP+FP) [TP/

Question 4

NPV formula?

Answer 4

TN/(TN+FN)

Question 5

Type 1 error?

Answer 5

Concluding there is a difference when there actually is no difference (p value)

Question 6

Type 2 error?

Answer 6

Concluding there is no difference when there actually is a difference (can decrease by increasing sample size)

Question 7

What is RR?

Answer 7

Measure strength of association between risk factor and disease (used in prospective cohort and RCT)

Question 8

Formula for RR?

Answer 8

(incidence of disease in those with risk factor) / (incidence of disease in those without risk factor)

Question 9

What is OR?

Answer 9

Estimate of RR in case control studies

Question 10

Formula for NNT?

Answer 10

1/absolute risk reduction

Question 11

What is absolute risk reduction?

Answer 11

Difference between incidence of event in control arm and incidence of event in study arm