Assignment task: Researchers enrolled 4000 women in a study and followed them every year for four years to determine the incidence rate of breast cancer. After the first year, 50 had a new diagnosis of breast cancer, and 150 were lost to follow-up. After year two, three had a new diagnosis of breast cancer, and another 125 had been lost to follow-up. After year three, another eighteen had new diagnoses of breast cancer, and 500 had been lost to follow-up. After four years, an additional 15 had new diagnoses with breast cancer, and 272 more had been lost to follow-up.
(Show your work and label your calculations)
Assume you didn't have data about which women were lost to follow up, and only had data about new cases in the 4 years- calculate the incidence proportion.