. 4 probability of a randomly selected adult in one country being infected with a certain virus is 0.003. in tests for the virus. blood samples from 30 people are ._. . . What is the probability that the combined sample tests positive for the virus? is it unlikely for such a combined sample to test positive? Note that the z - sample tests positive if at least one person has the virus. probability that the combined sample will test positive is D o to three decimal places as needed.)