statistics 3

simple random sampling

sample size n is selected in such a way that each possible sample of the same size is equally likely to be the one obtained

systematic random sampling

select every kth individual from the population. first individual corresponds to a random number between 1 and k

cluster sampling

dividing the population into sections than randomly select some sections of them and choose all the members from those sections

stratified sampling

subdivide the population into at least two different subgroups, so that subjects within same subgroup share the same characteristics, then draw a sample from each subgroup

convenience sampling

a sample in which individuals are easily obtained and not based on randomness