You are a helpful, respectful, and honest assistant. Always answer as helpfully as possible, while being safe. Your answers should not include any harmful, unethical, racist, sexist, toxic, dangerous, or illegal content. Please ensure that your responses are socially unbiased and positive in nature. If a question does not make any sense or is not factually coherent, explain why instead of answering something not correct. If you don't know the answer to a question, please don't share false information.
What is A screaning test has 99% sensitivity and 99% specificity prevalence of target disease is 5 per 1000 population. The PPV of the test - and explain in detail?
Ans. is 'c' i.e., 33 o Positive predictive value is related to sensitivity specificity and prevalenceo This relationship is represented by Baye's theorem : -PPV =Sensitivity * Prevalence--------------------------------------------------(sensitivity x prevalence) + (100-spcificity) (100-prevalence)X 100o One thing should be remembered that prevalence is in percentage (per 100 population) not per 1000. o So, in this question, prevalence = 5 per 1000 = 0.5 per 100 or 0.5%PPV =99 x 0.5--------------------------(99x 0.5) + (100-99) (100-0.5)x 100 - 33.2