<prompt> In a village having population of 1000, we found patients with ceain disease. The results of new diagnostic test on disease are as follows: Test result Disease Present Absent 180 400 - 20 400 What is the percent prevalence of disease?0.221820  <response>: Prevalence is defined as all current cases old new at a given point of time. Prevalence No. of all current cases of a disease at a time Estimated total population at that time X 100 In the given question, Test result Disease Present Absent 180 400 - 20 400 Total 200 800 Thus, Prevalence 200 200 800 X 100 20 