Stratified sampling is used to select a sample that is representative of different groups. If the groups are of different sizes, the number of items selected from each group will be proportional to ...

It’s a truism that even large samples can be misleading if they are biased or, as market and social researchers say, if they are not representative for the universe. Therefore, it is essential whether ...

The method of simple random sampling (METHOD=SRS) selects units with equal probability and without replacement. Each possible sample of n different units out of N has the same probability of being ...

The Journal of Geo-information Science recently published an online article on research led by researcher Lianfa Li and researcher Xiaomei Yang (Institute of Geographic Sciences and Natural Resources ...