1. Of 2,472 people who had received radiation treatment in childhood because of enlarged thymus, cancer of the thyroid developed in 24 and benign thyroid tumor developed in 52. A comparison group consisted of 3,055 children who had received no such treatment (brothers and sisters of those who had received radiation treatment). During the follow-up period, one of the comparison group developed thyroid cancer, but benign thyroid tumors developed in 6.
   1. Construct TWO 2x2 contingency tables for the data.One is for thyroid cancer and the other table is for benign thyroid tumors.
   2. Calculate the relative risk for benign thyroid tumors. Calculate the relative risk for thyroid cancer.
   3. Explain the results.