A relative risk (RR) of 1.0 indicates that there is no association between the exposure (prior tonsillectomy) and the outcome (Hodgkin's disease). From this we can conclude:

Here are the solutions to the questions:

1. In a study to determine whether tonsillectomy is associated with subsequent development of Hodgkin's disease, the estimated relative risk for those with prior tonsillectomy compared to those who had not had a tonsillectomy was found to be 1.0. From this we can conclude:
A relative risk (RR) of 1.0 indicates that there is no association between the exposure (prior tonsillectomy) and the outcome (Hodgkin's disease). This means the risk of developing Hodgkin's disease is the same for those who had a tonsillectomy and those who did not.

• A. Case fatality rate is a different measure and not directly related to the relative risk of developing a