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Question 1 In a screening test for diabetes used on 10,000 persons a cut-off level of 180mg of blood glucose per 100 ml or above was employed as being positive for diabetes. The prevalence of disease in this population is 5%. 150 people test positive for the disease of which 25 do not have disease. Set up a 2x2 table: Diabetes No Diabetes POS A B NEG C D A+C A [Choose] E] 10,000 375 B 25 E 150 _ 500 c 125 g 9850 _ 9475 F; D . 9500 ! N [Choose] A+B I [ Choose ] u A+C [ Choose ] C+D [ Choose ] B+D [ Choose ] Question 2 5.56 pts What is the sensitivity? O 20% 25% 50% O 75% Question 3 5.56 pts What is the specificity?Question 5 5.56 pts When the screening cut-off was lowered to 130mg of blood glucose per 100ml, 230 persons tested positive on the screening test. Of these, 66 did nto have disease. Set up a 2x2 table: Diabetes No Diabetes POS A B A+B NEG C D C+D A+C B+D N A I [Choose] a 9434 164 ' B 500 9 336 _ 230 _ C 66 t 9770 _ 10,000 _ D 9500 ; L_._____________.____________.s. N [Choose] A+B [ Choose ] 4P A+C V [ Choose ] 9434 164 C+D 500 336 230 B+D 66 9770 10,000 9500 Question 6 5.56 pts What is the sensitivity? O 67% 32.8% O 71.3% O 99.3%Question 10 5.56 pts In our example if the cut-off point is set higher than 180mg of blood glucose per 100ml, how would you expect this to affect the specificity and sensitivity of the test? The sensitivity will increase, specificity will decrease The sensitivity will increase, specificity will increase The sensitivity will decrease, specificity will decrease The sensitivity will decrease, specificity will increase Question 11 5.56 pts In the example above, assume the prevalence of diabetes increases from 5% to 8%. Using the sensitivity and specificity you estimated for 180 mg/ml cutpoint, compute the predictive value positive of a positive test. 87.7% 93.5%. 80.0%. O 99.7%.Question 13 5.56 pts Now assume you wanted to screen for an outcome where there was no gold standard. Instead of assessing the validity of the test by sensitivity and specificity, you can measure the reliability of two observers. Assume you have 100 samples and 2 observers both rate these samples as positive 5% of the times and both rate as negative 90% of the time. In addition Observer 1 identifies 3 cases as positive that Observer 2 did not find. Set up a 2x2 table to evaluate the reliability between the two observers Observer 1 Observer 2 Pos Neg Pos A B n1. Neg C D n2. n.1 n.2 N A V [ Choose ] 3 2 B 8 92 7 C 93 94 5 D 100 90N [ Choose ] n1. [ Choose ] n.1 [ Choose ] n2. [ Choose ] n.2 [ Choose ] Question 14 5.56 pts What is the overall percent agreement? 50% 95% 90% 5%Question 9 5.56 pts Match the following factors with the expected outcomes after lowering the screening cut-off point of a screening test? False positives V [ Choose ] Increase Decrease False negatives Sensitivity [ Choose 1 l Specicity [ Choose ] ' Positive predictive value [ Choose 1