4) A researcher is testing the effectiveness of two vaccines for preventing a disease. Two randomly selected treatment groups are chosen. 200 people were given vaccine A and 300 people were given vaccine B. During the trial period, 80 people who were given vaccine A and 105 people who were given vaccine B subsequently came down with the disease. Is vaccine B more effective than vaccine A? Use a = 005 . Your answer should show assumptions, hypotheses, and conclusions