During an outbreak of varicella, 250 school children were investigated. Of these, 125 met the case definition for varicella. Of the children who did not get sick with the disease, 80% were vaccinated for varicella. Of the children that were sick, 10% were vaccinated.

Construct a 2x2 table with the information from the section description.

What is the appropriate measure of association for this study? ?

Calculate the measure of association.