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{{WBRQuestion
{{WBRQuestion
|QuestionAuthor={{Rim}} {{Alison}}
|QuestionAuthor={{YD}} {{Alison}}
|ExamType=USMLE Step 1
|ExamType=USMLE Step 1
|MainCategory=Biostatistics/Epidemiology
|MainCategory=Biostatistics/Epidemiology
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|MainCategory=Biostatistics/Epidemiology
|MainCategory=Biostatistics/Epidemiology
|SubCategory=Vascular
|SubCategory=Vascular
|Prompt=The following table displays the results of a study investigating a new test in diagnosing aortic stiffness. Which of the following are the approximate sensitivity and specificity of the new test?
|Prompt=The following table displays the results of a study investigating a new test for diagnosing aortic stiffness. What are the approximate sensitivity and specificity of the new test?


[[Image:WBR Aortic Stiffness biostatistics.png|350px]]
[[Image:WBR Aortic Stiffness biostatistics.png|350px]]
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|AnswerB=Sensitivity = 83%
|AnswerB=Sensitivity = 83%
Specificity = 71%
Specificity = 71%
|AnswerBExp=71% corresponds to the positive predictive value (PPV). PPV is calculated by the following equation: PPV = TP/ (TP+FP)
|AnswerBExp=71% represents the positive predictive value (PPV) of the test. PPV is calculated using the following equation: PPV = TP/ (TP+FP)
|AnswerC=Sensitivity = 83%
|AnswerC=Sensitivity = 83%
Specificity = 83%
Specificity = 83%
|AnswerCExp=Both values correspond to sensitivity.
|AnswerCExp=Both values represent the test's sensitivity.
|AnswerD=Sensitivity = 67%
|AnswerD=Sensitivity = 67%
Specificity = 83%
Specificity = 83%
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|AnswerE=Sensitivity = 67%
|AnswerE=Sensitivity = 67%
Specificity = 67%
Specificity = 67%
|AnswerEExp=Both values correspond to specificity.
|AnswerEExp=Both values represent the test's specificity.
|EducationalObjectives=Sensitivity (%) = TP/ (TP+FN) x 100  
|EducationalObjectives=Sensitivity (%) = TP/ (TP+FN) x 100  
Specificity (%)= TN/ (TN + FP) x 100
Specificity (%)= TN/ (TN + FP) x 100

Revision as of 01:25, 17 September 2014

 
Author [[PageAuthor::Yazan Daaboul, M.D. (Reviewed by Alison Leibowitz)]]
Exam Type ExamType::USMLE Step 1
Main Category MainCategory::Biostatistics/Epidemiology
Sub Category SubCategory::Vascular
Prompt [[Prompt::The following table displays the results of a study investigating a new test for diagnosing aortic stiffness. 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% represents the positive predictive value (PPV) of the test. PPV is calculated using the following equation: PPV = TP/ (TP+FP)
Answer C [[AnswerC::Sensitivity = 83%

Specificity = 83%]]

Answer C Explanation AnswerCExp::Both values represent the test's 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 represent the test's 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
References: First Aid 2014 page 51]]

Approved Approved::Yes
Keyword WBRKeyword::Specificity, WBRKeyword::Sensitivity, WBRKeyword::calculation, WBRKeyword::equation, WBRKeyword::study, WBRKeyword::aortic stiffness
Linked Question Linked::
Order in Linked Questions LinkedOrder::