Biostatis........................................5 - ariadnac06
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Biostatis........................................5 - ariadnac06
|
10-29-2010, 09:12 AM
A study investigating a new test fro diagnosing acute myocardial infraction (MI) has just been released. The sensitivity of the test is 75% and the specificity is 80%. There are 200 patients who truly had an MI in the study and 4000 who truly did not. . How many false negative were in the study?
a) 50 b) 80 c) 120 d) 150 e) 380
10-29-2010, 09:23 AM
ya rt 400
now we 1st have to calculate TP sensitivity =TP/TP+FN 0.75=TP/200 0.75*200=TN TN=150 so FN=50
10-29-2010, 11:43 AM
y dont we take those who truly had MI as T.P?? i ve already solved this qs before n know tht abv is the correct ans,but i had this doubt..some1 plz help me see the difference..y do we take it as total n not TP
10-29-2010, 11:55 AM
hey docmp here when we say total true MI that means we include TN+FN [200]. we are missing some real MI ie we are getting some false negative
becoz these values we r getting from new test which has only 75% sensitivity and 80%specificity. i hope u understood now
10-29-2010, 04:30 PM
@basicq..thanks..n ya but still confused,hopefully qs will be lil clearer in test
@ariadna..where's this frm..coz i ve seen this before. |
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