Physical Impossibility

Some populations are uncountable or infinite to conduct a census. In this situation, it is impossible to consider all the elements of a population. Thus, a sample is necessary to obtain information from a population. For example, an environment engineer wants to determine the Ph level of a lake. It would be impossible to take all the water in the lake. Another example is the geographical size of the area that would be covered in the survey. Think about New York City, the population density is over 27,000 people square miles. Population density of Turkmenistan is 10.5 people per square km. Whereas the population density of Turkey is 104 people per square km. Now in your spare time, look at the maps of these countries and make a comparison of the sizes of these countries then you may see that how difficult it could be if you want to conduct a census in Turkmenistan.