This question is incomplete, the complete question is;
A screening examination was performed on 250 persons for factor X, which is found in disease Y. A definitive diagnosis for disease Y among the 250 persons had been obtained previously. The results are charted here:
Test Results Disease Present Disease Absent
Positive for Factor X 40 60
Negative for Factor X 10 140
a) Based on the information provided, The sensitivity of this test is expressed as: A. 30%. B. 80%. C. 56%. D. 70%. E. 7%.
b) Based on the information provided, The specificity of this test is expressed as: A. 30%. B. 80%. C. 56%. D. 70%. E. 7%.
Answer:
a)
The sensitivity of this test is expressed as 80%
Option B) 80% is the correct answer.
b)
The specificity of this test is expressed as 70%
Option D) 70% is the correct answer.
Step-by-step explanation:
Given the data in the question;
Test Results Disease Present Disease Absent
Positive for Factor X 40 60
Negative for Factor X 10 140
Number of persons affected by disease with positive factor of X = 40
Number of persons with negative factor of X without the disease = 140
Total number of persons affected by the disease = 40 + 10 = 50
Total number of persons not affected by the disease = 60 + 140 = 200
a) Sensitivity of the Test;
Sensitivity = [( Number of persons affected by disease with positive factor of X ) / ( Total number of persons affected by the disease )] × 100
we substitute
Sensitivity = [ 40 / 50 ] × 100
Sensitivity = 0.8 × 100
Sensitivity = 80%
Therefore, The sensitivity of this test is expressed as 80%
Option B) 80% is the correct answer.
b) The specificity of the test;
Specificity = [ ( Number of persons with negative factor of X without the disease) / ( Total number of persons not affected by the disease ) ] × 100
we substitute
Specificity = [ 140 / 200 ] × 100
Specificity = 0.7 × 100
Specificity = 70%
Therefore, The specificity of this test is expressed as 70%
Option D) 70% is the correct answer.
