Consider a source population consisting of 1,000 adults. Assume that no subjects moved in or out of the population over the next 12 years, but there were some deaths

Consider a source population consisting of 1,000 adults. Assume that no subjects moved in or out of the population over the next 12 years, but there were some deaths. Among the 1,000 subjects, 990 remained alive and free of cancer from 2001 to 2012. Events in the other 10 subjects are depicted in the image below. Subjects 1, 2, 3, and 4 were known to have lung cancer in 2001. The beginning of a dashed line indicates a newly diagnosed lung cancer, and the dashed lines indicate the ongoing presence of lung cancer in living subjects (dashed lines), and deaths are indicated in the figure. 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 Question 1: What was the prevalence of lung cancer in 2009? Question 2: What was the prevalence of lung cancer in 2005? Question 3: What was the prevalence of lung cancer in 2010? Question 4: What was the cumulative incidence of lung cancer from 2003 to 2012?