You want to test the effectiveness of a new vaccine against the chicken pox. you inject the vaccine into 100 children, exposed the children to the virus. after a few days, you record whether or not each child contracted the chicken pox. what is one error in the set up of this experiment? a. too many children were tested. b. the dependent variable is not whether or not the child contracted the virus. c. both a and b d. there should have been a control group that was exposed to the virus, but did not get the vaccine.