Description: A researcher was testing the effectiveness of vaccines on the swine disease called PRRS. The researcher randomly split a group of 650 swine into 13 groups of 50 swine. Each group was randomly assigned to one of 4 treatment groups. Each treatment group was given the specific treatment and was then injected with the PRRS virus. The results show the number of swine that test positive for PRRS 30 days after infection.