Question

1. In the following two situations, either stratified random sampling method or cluster sampling method is used.

(1) Identify the sampling method used, and (2) briefly justify your choice.

1. To get an idea of how much detached houses in the city of Vancouver cost these days, Joe went to a real estate web site (like realtor.ca) to get some information. He divided the city of Vancouver into 20 districts or communities; randomly selected 5 of them; and all detached houses (that are listed on the web site) within those 5 districts were chosen.

2. To get an idea of how much detached houses in the city of Vancouver cost these days, Joe went to a real estate web site (like realtor.ca) to get some information. He divided the city of Vancouver into 20 districts or communities; randomly selected 5 detached houses from each district; and the 100 (20 districts times 5 houses per district) detached houses formed the sample.

Note: In practice, geographic factor should not be used to do the stratification. It’s used here only for the sake of illustration.

Answer 1

Cluster Sampling is a method where the target population is divided into multiple clusters. Some of these clusters are selected randomly for sampling . In cluster sampling Selection of the sample is done by randomly selected clusters and including all the members from these clusters.

Stratified Sampling is a probability sampling method, also called random quota sampling, where a large population is divided into unique, homogeneous strata and further, members from these strata are randomly selected to form a sample. In stratified sampling Selection of the sample is done by randomly selecting members from various formed strata.

a) CLUSTER SAMPLING

explanation- Because first joe first divide the city into 20 different districts (say clusters) and then randomly select 5 district and all the detached houses within those 5 districts were chosen , its like 5 clusters are randomly chosen and all the members of this cluster are included . (As in the case of cluster sampling clusters are selected randomly and then all the members of the cluster are included in the sample)

b) STRATIFIED SAMPLING

explanation- Because first joe first divide the city into 20 different districts (say strata) and then randomly select 5 detached houses from each district As in case of stratified sampling samples from each strata is taken (here sample from each district is taken)