Investigators conducting a study regarding the effects of water pollution and peptic ulcer disease obtained the following data:

a population of 9,000 men and women, aged 45 years, were examined on january 1, 1985. of these people, 6,000 were exposed to toxins in the local water supply and 3,000 were not. at the time of this examination, 90 cases of peptic ulcer disease were discovered; 60 of these cases were among those exposed to toxins in their local water.

all the people at the initial examination who were free from peptic ulcer disease were followed with repeat exams throughout 1985. all repeat exams were completed on december 31, 1985. this study revealed 268 new cases in the total group; of these, 238 cases were among those exposed to toxins in their local water.

1.) calculate the prevalence per 1,000 people of peptic ulcer disease on january 1, 1986 among the exposed. be sure to review the dates for the denominator of the prevalence!

2.) calculate the prevalence per 1,000 people of peptic ulcer disease on january 1, 1986 among the non-exposed.

3.) calculate the 1985 incidence rate per 1,000 people of peptic ulcer disease among the exposed.

4.) calculate the 1985 incidence rate per 1,000 people of peptic ulcer disease among the non-exposed.