[R] bootstraping sensitivity and specificity
lamac_k at hotmail.com
Thu Apr 24 15:25:23 CEST 2003
Dear all, I have a standard method and two alternatives to perform a test,
called method A and method B.
I have calculated the sensitivity and specificity for
standard method vs. method A and standard method vs. method B.
Hence, I have two sensitivity values an two specificity values.
To be clear, sensitivity and specificity was calculated from:
Disease(A) No Disease(Ac) Total
Positive Screen(T) a b a+b
Negative Screen(Tc) c d c+d
Total a+c b+d a+b+c+d
where sensitivity: P(T | A)=a/(a+c) and
specificity: P(Tc | Ac)=d/(b+d).
How can I compare this quantities? That is, how method have high sensitivity
Could I get the empirical distributions for sensitivity and specificity from
If yes, Could I sampling from the set of "all" contingency tables
with given marginals, and works only if the marginals are positive?
It is the technique used by chisq.test when simulate.p.value is TRUE.
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