Question

For the following situation identify the sampling method used.

The Florida Fish and Wildlife Conservation Commission manatee mortality database website has information on cause of death and size for all manatees killed off Florida waters.We decide to divide the cause of death into watercraft, natural causes, stress, and other. Within each of these groups, a random sample of 25 manatees are selected.

	A.	systematic sampling
	B.	stratified sampling
	C.	simple random sampling
	D.	cluster sampling

Answer 1

For the given situation the method of sampling used here is known as Stratified Sampling method.

Here at first we justify the reason why the other sampling method is not taken here. First of all it is not a simple random sampling because the sample for the experiment are not select randomly frome whole population . We divide the population in four groups and then take sample from each which is against the simple random sampling. Trivially it is not systematic because here we divide the whole population into 4 groups according to some homogeneity characteristic . We have not arrange the population unit for grouping purpose which is used in systematic sampling for grouping purposes.

It is not clustering sampling because in cluster sampling homogeneity is between the groups and we take all unit of one cluster as a sample from the whole population but here we select 25units from each group . Hence it is not a cluster sampling.

Lastly it is a Stratified sampling method because we divide the whole population into four categories. And it is very clear unit within the groups are homogeneous. And select 25 units from each groups .Hence each groups can be considered as a 'stratum' and the sampling method is stratified sampling method.