Sampling Methods

1. Sampling Methods Project Trimester-SS-2006/08

2. Convenience Sampling • Population elements are selected based on the judgement of the researcher. • Chooses the elements to be included because he/she believes they are representative of the population

3. Cluster Random Sampling • The target population is divided into mutually exclusive and collectively exhaustive clusters or sub-populations. • Then a random sample of clusters is selected • For each selected cluster, either all the elements are selected or a sample of elements is drawn probabilistically.

4. Cluster Random Sampling • Take the population map. • Divide it into equal clusters • Assign each cluster a random number. • Select the cluster/s on the basis of a pre-decided rule. • Divide the selected cluster into sub-clusters. • Repeat steps 2-4 until you get a manageable sub-cluster.

5. Example

6. Divide Map/Population into clusters

7. Assign Random numbers • http://www.graphpad.com/quickcalcs/randomn2.cfm • Select Random numbers on basis of pre-decided rules. E.g. only even numbers • Select 1 or more clusters on basis of pre-decided rules e.g. Divisible by 4 • Repeat till you get desired number of clusters/sub-clusters

9. Rule: Numbers ending with 8

10. Rule 2: Select cluster exactly divisible by 8

12. Thank You!!