A study was conducted in a medical school hospital to evaluate whether visual inspection of the cervix (by speculum examination) would be a useful screening test for cervical cancer. Logistically, pap smears are not always possible to perform in the field and a simple visual inspection test, if found valid and reliable, could be a life saving procedure in such settings.

660 consecutive patients with suspected cervical cancer who attended an obstetrics and gynecology out-patient clinic were admitted to a referral hospital. A trained nurse performed visual inspection of the cervix on all of these patients and classified the results as positive or negative. Subsequently, another investigator independently performed cervical biopsy (gold standard) on all of the patients. The investigators were blinded to each other's findings. 330 of the 660 patients had cervical cancer on histopathological (biopsy) examination. The results [fictitious data] are shown below:

Data for visual inspection vs. histopathology

	Histopathology (biopsy)
		+	--
Visual inspection test	+	310	30	340
--	20	300	320
		330	330	660

Flag question: Question 1

Calculate sensitivity(do not include a % in your answer)

Flag question: Question 2

Which of the following is the best description of this test's sensitivity( where XX% is the result calculated above)?

Group of answer choices

A-Among those who tested positive for cervical cancer on visual inspection, XX% truly had cervical cancer

B-Among those without cervical cancer (i.e. negative cervical biopsy), XX% tested negative for cervical cancer on visual inspection

C-Among those with cervical cancer (i.e. positive cervical biopsy), XX% tested positive for cervical cancer on visual inspection

D-Among those who tested negative for cervical cancer on visual inspection, XX% truly did not have cervical cancer

Flag question: Question 3

Calculate specificity(do not include a % in your answer). Round your answer to the nearest tenth (0.1).

Flag question: Question 4

Which of the following is the best description of this test's specificity (where XX% is the result calculated above)?

Group of answer choices

A-Among those who tested positive for cervical cancer on visual inspection, XX% truly had cervical cancer

B-Among those without cervical cancer (i.e. negative cervical biopsy), XX% tested negative for cervical cancer on visual inspection

C-Among those with cervical cancer (i.e. positive cervical biopsy), XX% tested positive for cervical cancer on visual inspection.

D-Among those who tested negative for cervical cancer on visual inspection, XX% truly did not have cervical cancer.

Flag question: Question 5

Calculate positive predictive value [PPV](do not include a % in your answer)

Flag question: Question 6

Which of the following is the best description of this test's positive predictive value (where XX% is the result calculated above)?

Group of answer choices

A-Among those who tested positive for cervical cancer on visual inspection, XX% truly had cervical cancer

B-Among those without cervical cancer (i.e. negative cervical biopsy), XX% tested negative for cervical cancer on visual inspection

C-Among those with cervical cancer (i.e. positive cervical biopsy), XX% tested positive for cervical cancer on visual inspection.

D-Among those who tested negative for cervical cancer on visual inspection, XX% truly did not have cervical cancer.

Flag question: Question 7

Calculate negative predictive value [NPV] (do not include a % in your answer)

Flag question: Question 8Question 81 pts

Which of the following is the best description of this test's negative predictive value (where XX% is the result calculated above):

Group of answer choices

A-Among those who tested positive for cervical cancer on visual inspection, XX% truly had cervical cancer

B-Among those without cervical cancer (i.e. negative cervical biopsy), XX% tested negative for cervical cancer on visual inspection

C-Among those with cervical cancer (i.e. positive cervical biopsy), XX% tested positive for cervical cancer on visual inspection.

D-Among those who tested negative for cervical cancer on visual inspection, XX% truly did not have cervical cancer.

Flag question: Question 9

Based on the above results, which of the following best describes the usefulness of the the visual inspection test is as a screening test for cancer of the cervix?

Group of answer choices

A-It is not a useful screening test, because specificity if less than sensitivity.

B-It is a useful screening test because senstivity and specificity are both relatively high.

C-It is a useful screening test because sensitivity is higher than negative predicative value

D-It is not a useful screening test, because sensitivity is too low.

Flag question: Question 10

What was the overall prevalence of cervical cancer in the above study population? (Do not include a % in your answer)