Question

You want to test the effectiveness of a new vaccine against the chicken pox. You inject the vaccine into 100 children, keep 100 children as the control group and expose all of the children to the virus. You send the children that received the vaccine back to their daily life and kept those that did not receive the vaccine in isolation. After a few days, you record whether or not each child contracted the chicken pox.

Why does the bolded statement above decrease the validity of the experimental results?
A.
You should have sent the children that did not receive the vaccine back to their daily lives and kept those that did receive the vaccine in isolation.
B.
You should send half of each group (experimental and control) to each location.
C.
Both the experimental group and the control group should be treated the same except for the one factor being tested.
D.
You shouldn't have tested so many children.

Answer 1

Explanation:

Option C is the correct answer