Question

Of the control group 100 did not have the disease, 10 had a history of the risk factor. Of the 100 people with the disease, 20 had a history of the risk factor. What is the odds ratio?

Answer 1

The odds ratio is a measure of the association between a risk factor and a disease. It is calculated by dividing the odds of the risk factor in the disease group by the odds of the risk factor in the control group.

Step-by-step explanation:

The odds ratio is a measure of the association between a risk factor and a disease. It is calculated by dividing the odds of the risk factor in the disease group by the odds of the risk factor in the control group.

In this case, the odds of having a history of the risk factor among those with the disease is 20/80, and the odds of having a history of the risk factor among those without the disease is 10/90. The odds ratio is a measure of the association between a risk factor and a disease.

It is calculated by dividing the odds of the risk factor in the disease group by the odds of the risk factor in the control group.

Therefore, the odds ratio is (20/80) / (10/90) = 2.25.

So, the odds of having a history of the risk factor in those with the disease are 2.25 times greater than the odds of having a history of the risk factor in those without the disease.