WBR0418: Difference between revisions
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|Prompt=A study is interested in investigating a new test in diagnosing aortic stiffness. The following table shows the results of the study. What are the approximate sensitivity and specificity of the new test? | |Prompt=A study is interested in investigating a new test in diagnosing aortic stiffness. The following table shows the results of the study. What are the approximate sensitivity and specificity of the new test? | ||
[[Image:WBR Aortic Stiffness biostatistics.png]] | [[Image:WBR Aortic Stiffness biostatistics.png|350px]] | ||
|Explanation=Sensitivity (%) = TP/ (TP+FN) x 100 = 100/(100+20) x 100 = (100/120) x 100= 83% | |Explanation=Sensitivity (%) = TP/ (TP+FN) x 100 = 100/(100+20) x 100 = (100/120) x 100= 83% | ||
Specificity (%) = TN/ (TN + FP) x 100 = 80/(80+40) x 100 = (80/120) x 100 = 67% | Specificity (%) = TN/ (TN + FP) x 100 = 80/(80+40) x 100 = (80/120) x 100 = 67% | ||
[[Image:WBR Aortic Stiffness biostatistics explanation.png]] | [[Image:WBR Aortic Stiffness biostatistics explanation.png|350px]] | ||
Educational Objective: | |||
Sensitivity (%) = TP/ (TP+FN) x 100 | |||
Specificity (%)= TN/ (TN + FP) x 100 | |||
|AnswerA=Sensitivity = 83% | |AnswerA=Sensitivity = 83% | ||
Specificity = 67% | Specificity = 67% | ||
Revision as of 02:19, 15 September 2013
| Author | [[PageAuthor::Rim Halaby, M.D. [1]]] |
|---|---|
| Exam Type | ExamType::USMLE Step 1 |
| Main Category | MainCategory::Biostatistics/ Epidemiology |
| Sub Category | SubCategory::Vascular |
| Prompt | [[Prompt::A study is interested in investigating a new test in diagnosing aortic stiffness. The following table shows the results of the study. What are the approximate sensitivity and specificity of the new test?
|
| Answer A | [[AnswerA::Sensitivity = 83%
Specificity = 67%]] |
| Answer A Explanation | [[AnswerAExp::Sensitivity (%) = TP/ (TP+FN) x 100 = 83%
Specificity (%) = TN/ (TN + FP) x 100 = 67%]] |
| Answer B | [[AnswerB::Sensitivity = 83%
Specificity = 71%]] |
| Answer B Explanation | AnswerBExp::71% corresponds to the positive predictive value (PPV). PPV is calculated by the following equation: PPV = TP/ (TP+FP) |
| Answer C | [[AnswerC::Sensitivity = 83%
Specificity = 83%]] |
| Answer C Explanation | AnswerCExp::Both values correspond to sensitivity. |
| Answer D | [[AnswerD::Sensitivity = 67%
Specificity = 83%]] |
| Answer D Explanation | AnswerDExp::The inverse is true. |
| Answer E | [[AnswerE::Sensitivity = 67%
Specificity = 67%]] |
| Answer E Explanation | AnswerEExp::Both values correspond to specificity. |
| Right Answer | RightAnswer::A |
| Explanation | [[Explanation::Sensitivity (%) = TP/ (TP+FN) x 100 = 100/(100+20) x 100 = (100/120) x 100= 83%
Specificity (%) = TN/ (TN + FP) x 100 = 80/(80+40) x 100 = (80/120) x 100 = 67%
Educational Objective:
Sensitivity (%) = TP/ (TP+FN) x 100
Specificity (%)= TN/ (TN + FP) x 100 |
| Approved | Approved::No |
| Keyword | |
| Linked Question | Linked:: |
| Order in Linked Questions | LinkedOrder:: |
