As X became 22 on 4/2/2012 , but he joined study on 1/3/2012
So we count from 1/3/2012 , but he died on 1/4/2012...
And we know Initial exposed to risk at age x for \(D_i=1 \) is from x+a_i to x+1
Hence we count from 1/3/2012 to 3/2/2013..... 366-31-29+31+3
Therefore \( E_{22}=340 \)
Last edited: Jan 11, 2015