What factors must one consider in making a decision on sample size? How are these factors different for quantitative and qualitative studies?

Sampling is collecting information about some members of population Sampling has the ability to obtain useful inferences about large populations even from modest samples

In quantitative sampling probability approach is used . One of the most important aspects of quantitative sampling is the level of precision called as sampling error . It is the range where the true value of population is estimated to be normally expressed in percentage often conducted in political campaigns . One approach is to use entire population as sample which in real world is impossible due to high cost

involved . However the most attractive way is the census for small population of 200 t0 500 is feasible in quantitative research

The qualitative researches normally use non-probability sampling because it does not aim to produce a statistical sample of the entire population . For example purposive is the common techniques used in qualitative investigation where a non-random number of people are interviewed with a strict criterion for the people to be interviewed Normally in the qualitative study it 's the characteristics of the individuals which play a strong role to become part of the research . In qualitative research the data collection and analysis is quite intensive which makes it important to think carefully the sampling strategy Compared to quantitative techniques , in qualitative research the sampling size is small which are supported by interviews , narratives and focus groups which can provide an overall view of research question

Despite being using different approaches of sampling , there also an additional factor which needs to taken into consideration such as is the sampling random , or complex . What is the research question and how much resources a researcher have at hand . Based on this information only then a true sample size can be determined .Reference

George A . Marcoulides (1998 .Modern Methods for Business Research Lawrence Erlbaum Associates...