n the attached figure, three separate cross-sectional surveys were performed on October 1, 2004; April 1, 2005; and September 30, 2005. Notice there are different people taking the survey at each time point depending on who was sick, who recovered, or who died. What factors can contribute to errors in interpretation at each time point? In your answer, please include a discussion regarding the study samples surveyed at each time point and how they are different from or similar to one another.