Year 4

Question 1

How do you calculate the sensitivity

Answer 1

sensitivity is the proportion of people with the disease that identified with the test. The sensitivity is calculated as (True positives)/ (True positives + False negatives)

Question 2

How do you calculate specificity

Answer 2

specificity is defined as the proportion of people who test negative among all those who actually do not have the disease. It is calculated as (True negatives)/ (True negatives + False positives)

Question 3

How do you calculate negative predictive value?

Answer 3

negative predictive value (NPV) is the probability that following a negative test result, the individual will turn out not to have the disease. The NPV is calculated as (True negatives)/ (True negatives + False negatives)

Question 4

how do you calculate positive predictive value?

Answer 4

The PPV is calculated as (True positives)/(True positives + False positives)

Question 5

How do you calculate absolute risk reduction

Answer 5

ARR is calculated by taking the absolute risk (AR) of the placebo group and subtracting from it the AR of the therapeutic group.

Question 6

how do you calculate NNT

Answer 6

The NNT is calculated by taking the reciprocal of the absolute risk reduction. In this case, it would be 1/(22.4% - 14%) = 1/(8.4%) = 12

Question 7

how do you calculate the relative risk reduction

Answer 7

The relative risk reduction is calculated by taking the difference between the absolute risk in the control and therapeutic groups and dividing it by the absolute risk of the control group.