A study published in 1990 (Amer J. Pub Health 80:pp 209-210) investigated the occurrence of HIV infection among prisoners in Nevada. Of 1100 prison inmates who were tested for HIV upon admission to the prison system, 35 were found to be infected. All uninfected prisoners were followed for a total of 1200 person-years and retested for HIV upon release from prison. Five of the uninfected inmates demonstrated evidence of new HIV infection. 1. Calculate the prevalence of HIV infection among the incoming prisoners in Nevada prisoners before the study and after the study. 2. Based on the above information, calculate the incidence rate of HIV infection among prisoners in the Nevada prisons. Express the incidence rate in terms of cases per 1000 person-years.