4 A population of 100 healthy men was followed for the devel

4. A population of 100 healthy men was followed for the development of prostate cancer as described herein: After being followed for 5 years, 20 men developed prostate cancer. Another 10 men were followed for 1 year and then were lost. The remaining men who never developed the disease were followed for 10 years. Calculate the number of person-years of observation accrued by this population.

Solution

Solution:

Given

100 healthy men

followed for 5 years, 20 men

10 men were followed for 1 year

Now we will calculate the number of person-years of observation accrued by this population.

First we have

20 men and 5 years so,

20 x 5 = 100

Later Another 10 men were followed for 1 year so,

10 x 1 = 10

Actually we have 100 healthy men in which 30 of them are not healthy. So,

remaining men who never developed the disease were followed for 10 years are

70 x 10 = 700

Now we will add all the above results

= 100 + 10 + 700

= 810

Hence 810 is the observation accrued by this population.