If the population were studying is small we can modify the sample size we calculated in the above formula by using this equation. Therefore the sample size for N 120000 can be calculated as 120000 196 2 005 1-005 005 2 120000 1 196 2 005 1-005 005 2 Therefore it is proved that as the population size increases to be very large it becomes irrelevant in the computation of the sample size. To use this formula the desired level of precision the population size should be known.
Then you can use the formula nZ2s2d2.
E margin of error. If N100 then the corrected sample size would be 18600285 6526 or 66. Therefore the sample size for N 120000 can be calculated as 120000 196 2 005 1-005 005 2 120000 1 196 2 005 1-005 005 2 Therefore it is proved that as the population size increases to be very large it becomes irrelevant in the computation of the sample size. Your sample size for a survey is based on the question with the greatest variability in the sampled population.