Of 2,872 individuals who had received radiation treatment in childhood because of enlarged thymus, 24 developed cancer of the thyroid A comparison group consisted of 5,055 children who had received no...

Of 2,872 individuals who had received radiation treatment in childhood because of enlarged thymus, 24 developed cancer of the thyroid A comparison group consisted of 5,055 children who had received no such treatment (brothers and sisters of those who had received radiotheraphy), six in the comparison group developed thyroid cancer after follow-up. Calculate the appropriate measure of association for thyroid cancer. Provide an interpretation for this.