One hundred men and 100 women were included in a prospective cohort study. During the 1stof the study, 20 participants were diagnosed with heart disease. Thirty people were diagnosed with heart disease in year 2. No participants died during the study. Twenty participants were lost to follow-up in year 1 and ten were lost to follow-up in year 2.

Show your work or describe the process.

1.Calculatetheperson-timethat the participants contributed to the studyduring the first year?

2.Calculatetheperson-timethat the participants contributed to the studyduring the second year?

3. Calculate the incidence density (per 1,000person-years) for the study.

4.How many person-years didwomencontribute to the study?