A researcher wishes to test the effectiveness of a flu vaccination. 150 people are vaccinated, 180 people are vaccinated with a placebo, and 100 people are not vaccinated. The number in each group who later caught the flu was recorded. The results are shown below.
|
Vaccinated
|
Placebo
|
Control
|
|
Caught the flu
|
8
|
19
|
21
|
|
Did not catch the flu
|
142
|
161
|
79
|
Find and interpret the relative risk of catching the flu, comparing those who were vaccinated to those in the control group.