Complex sentence: However, note that this conclusion applies to a "screening" scenario, in which there are no distinguishing signs or symptoms so that pre-test beliefs about a given subject are equal to the population's background prevalence.
Split into simpler sentences: However, note that this conclusion applies to a "screening" scenario, in which there are no distinguishing signs or symptoms. The consequence of the screening scenario is that pre-test beliefs about a given subject are equal to the population's background prevalence.