Stats

Question 1

Formula for Sensitivity

Answer 1

proportion of people with the disease who test positive

(TP / TP + FN)

Question 2

Formula for Specificity

Answer 2

proportion of people without the disease who test negative

(TN/ TN + FP)

Question 3

Formula for PPV?

Answer 3

TP/ TP + FP

Question 4

Formula for NPV?

Answer 4

TN/ TN + FN

Question 5

How to convert from a pre-test probability to post test probability given a likelihood ratio

Answer 5

Question 6

What are ROC curves

Answer 6

Receiver Operating Characteristic curves

Compare sensitivity vs Specificity (technically 1- specificity) at different points.

Best to be in the top left corner.

Compare them for different test by comparing the area under the curve.

Question 7

What is Standard error

Answer 7

standard deviation of the sampling distribution`