Suppose a value of 130 mg/dl or higher was considered positive and the prevalenc
ID: 3043008 • Letter: S
Question
Suppose a value of 130 mg/dl or higher was considered positive and the prevalence of undetected diabetes remained the same as questions 2-3 ( available for refrence below)
How would you predict sensitivity (Se) would be affected by this change? Why? Guess without calculation!
Sensitivity would be [ Select one] ["increased", "no change", "decreased"] because [ Select one] ["TP", "TN", "FP", "FN"] will DECREASE
How would you predict Specificity would be affected by this change ? Why? Guess without calculation!
Specificity would be [ Select ONE] ["decreased", "", "increased", "no change"] because [ Select ONE ] ["TP", "FN", "FP", "TN"] will INCREASE.
Please compare sensitivity and specificity and observe how the number in cell a, b, c, and d is changing when you change the cutoff point from high to low (from 180 mg/dl to 130 mg/dl) . Sensitivity = TP /(TP + FN) = a/(a+c) Specificity = TN /(FP + TN) = b/(b+d
question 2 -3 for reference
A group of 10,000 people who were asymptomatic for diabetes were screened for diabetes by a test measuring blood serum sugar content. A value of 180 mg/dl or higher was considered positive. The results were compared with those of a second and definitive test (gold standard) which correctly detected all cases and non-cases. The results were as follows: Definitive Test Negative Totals Positive Positive 34 20 54 Screening Test Negative 116 9830 9946 Totals 150 9850 10000 What is the prevalence of undetected diabetes? (i.e., before screening). 3.4 % O 0.5 % 0 1.0% 1.5 %Explanation / Answer
a) prevalence = 150/10000 * 100 = 1.5%
b) sensitivity = (34/150) * 100 = 22.7%
c) specificity = (9830/9850) * 100 = 99.8%
sensitivity would be increased because 'FP' will decrease.
specificity would be decreased, because ' TN' will increase.
Related Questions
drjack9650@gmail.com
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.