Biostatistics Q1 - desperatehh

[ArchivalUser]

Q1. The prevalence of tuberculosis in one inner city community was estimated to be high as 10%. To control the spread of the disease, the local public health department is debating instituting a community-wide screening program. Although the test they are planning to use is inferior to the most commonly used tuberculosis screening test, it has the advantage of being cost effective. In preliminary trials, the new screening test was found to have a sensitivity of 70% and specificity of 90%. Based on this information, the physician should recommend that the new screening test should NOT be used because the new test
(A) has a negative predicative value less than 50%
(B) has a positive predicative value less than 50%
© is accurate less than 50% of the time
(D)is less than 50% reliable
(E) is subject to selection bias

This was posted before in the Forum about a year ago, but the answers were confusing. Please Discuss.

[ArchivalUser]

i guess A
coz when u put a screening test u need it to have a high sensitivity to detect all possible diseased ppl and high sensitivity means high negative predictive value

and this test has low sensitivity which means low negative predictive value
and that is why it is not a good test

[ArchivalUser]

my above talk was without calculation
but if we calculate it seems that this test has NPV more than 50%
and PPV less than 50% so the A is not right answer but i am not convienced about the B
this question seems stupid hehe like why they put the 50% in the question why should we judge a test by 50% values