important biostatistic concept question
 

here is a question i don't have an answer to, plz help:

10 patients was followed for 5 years for the development of a disease. 3 out of the 10 quitted the study during variable times in study period. 4 out of the remaining 7 developed the disease during variable times in the study period. what is the incidence of the disease?
ps: im not sure if it is incidence during 5 years or during a year. maybe it is the latter. any thoughts????

I think you are looking for the incidence rate in person time years. You should be given the time each participant was followed for to calculate that.
Number of new cases/total amount in years.
That's what I know about this