1. CLUSTER SAMPLING a survey of selected groups within a population the entire population is divided into groups (clusters), and a random sample of these clusters are selected used when certain groups called “natural groupings” are likely to be representative of the entire population

3. Example: The city of London wants to find out how effective the nutritious meals are in elementary schools across the city and surrounding counties. All elementary students in a local school district 11 different elementary schools in the local school district population groups (clusters)

4. Example: every student in the 4 selected elementary schools 4 elementary schools from the l1 possible elementary schools obtain a simple random sample sample

5. Process:  DETERMINE whether or not the population contains “natural” groupings that are representative of the entire population.  DIVIDE the population into groups (clusters).  SELECT a random sample from these clusters.  CONDUCT a survey of the random sample.  ANALYZE the data using statistical techniques.

6. Advantages: cheap, quick, and easy the researcher is able to use a larger sample size

7. Disadvantages: least representative of the population out of all the types of probability samples high sampling error caused by limited clusters