Question

In: Biology

100 people are tested for disease. 30 people have the disease and 70 do not. There...

100 people are tested for disease. 30 people have the disease and 70 do not. There were 20 true positives and 37 true negatives.
Part 1: What was the sensitivity of the test? Be sure to give context.
Part 2: What was the specificity of the test? Be sure to give context.
Part 3: What was the positive predictive value of the test? Be sure to give context.
Part 4: What was the accuracy of the test? Be sure to give context.

Expert Solution

100 people were Tested for the disease.

30 people have the disease and 70 do not. There were 20 true positives and 37 true negatives.

True positive (TP) = 20

True negative (TN) = 37

False positive (FP) = 30 - 20 = 10

False negative (FN) = 70 - 37 = 33

1) Sensitivity =

=

= 20/53 = 0.377

? Sensitivity is the ability of the test to correctly identify those with the disease i.e. true positive.

So the sensitivity of the test is 0.377

2) Specificity =

=

= 37/47 = 0.787

? Specificity is the ability of a test to correctly identify those without the disease i.e. true negative.

So the specificity of the test is 0.787

3) Positive predictive value =

=

= 20/57

= 0.351

? Positive predictive value is the proportion that the subjects with a positive screening truly have the disease.

So the positive predictive value is 0.351

4) Accuracy of the test

= Correctly predicted class × 100% Total Testing class

= TP + TN × 100% TP + TN + FP + FN

= 20 + 37 × 100% 100

= 57 %

Accuracy is the percentage of correctly classified instances i.e. percentage of true results in the population.

The accuracy of the test is 57%

gladiator answered 2 years ago

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