Clarification RE: HW 7 q#1

Clarification RE: HW 7 q#1

by Safyer Mckenzie-Sampson -

Hi Dr. Chan,

I wanted to make sure that I understand how to enter data for the diagti command so that it matches the information given to us in the urinary cotnine-self report table. I understand that the "true positives" would be the 402 individuals who had EC+ and SR+, and the "true negatives" are the 1481 individuals who had EC - and SR-. However, I'm unsure if its 113 false negatives and 159 false positives, or vice versa?

For clarity, I'm asking whether the order should be: 402 159 113 1481 or 402 113 159 1481?

Re: Clarification RE: HW 7 q#1

by June Chan -
Hi Safyre, here's some additional info from the STATA help site:
https://www.stata.com/stb/stb59/sbe36_1/diagt.hlp

"^diagt^ displays various summary statistics for a diagnostic test,
compared to patients' true disease status, sensitivity, specificity,
and predictive values, from a 2x2 table. ... #a #b #c #d are, respectively, the numbers of true positives
(diseased subjects with correct positive test results), false negatives
(disease, but negative test), false positives (no disease, but positive
test) and true negatives (no disease, negative test)."

best wishes!