Question

A screening examination was performed on 250 persons for human papilloma virus (HPV), which is found in cervical cancer. A definitive diagnosis for cervical cancer among the 250 subjects had been obtain previously. There were 60 subject who tested positive for HPV who also had cervical cancer, 40 subjects who tested positive for HPV but did not have cervical cancer. There were 10 subjects who tested negative for HPV, but had cervical cancer and 140 subjects who tested negative for HPV, who did not have cervical cancer. (Hint: create a 2 X 2 table). The specificity of this test is expressed as: I need the "specificity" of this test

Answer 1

specificty:

specificity identifies with the test's capacity to accurately dismiss sound patients without a condition .think about the case of a restorative test for diagnosing a sickness.specificity of a test is the extent of solid patients known not to have the malady ,who will test negative for it.

2X2 table:

	disease	no disease
test positive	true positive	false positive
test negative	false negative	true negative

from the given data substitute the values according to the above table

	cervical cancer	no carvical cancer
test positive	60(ture +ve)	40(false +ve)
test negative	10(false -ve)	140(true -ve)

now specificity is given by

specificity=true negative /total no. of postitivities

total no.of positivities=true positive + false negative

specificity=true negative/(true positive + false negative)

now substitute the values by using the above 2X2 table

then

specificity=140/(140+40)

=140/180

specificity=0.7777777

now percentage of specificity is given by

%specificiy=0.777777*100

%specificty=77.7777%