Question

Identify the sampling techniques​ used, and discuss potential sources of bias​ (if any). Explain.

After a tornado, a disaster area is divided into 150 equal grids. Fifty of the grids are​ selected, and every occupied household in the grid is interviewed to help focus relief efforts on what residents require the most.

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What type of sampling is​ used?

a) Stratified sampling is​ used, since the disaster area is divided into​ grids, and some of those grids are selected and everyone in those grids is interviewed.

b) Cluster sampling is​ used, since the disaster area is divded into​ grids, and a random sample is taken from each grid.

c) Cluster sampling is​ used, since the disaster area is divided into​ grids, and some of those grids are selected and everyone in those grids is interviewed.

d) Stratified sampling is​ used, since the disaster area is divded into​ grids, and a random sample is taken from each grid

-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------What potential sources of bias are​ present, if​ any? Select all that apply

a) The sample only consists of grids that are easy to get. These grids may not be representative of the population.

b) Certain grids may have been much more severely damaged than others. Severely damaged grids may have fewer occupied households.

c) Certain grids may have been much more severely damaged than others. The grids that are selected may not be representative in terms of damage.

d) There are no potential sources of bias.

Answer 1

1) cluster sampling technique is used

Cluster sampling is​ used, since the disaster area is divided into​ grids, and some of those grids are selected and everyone in those grids is interviewed

2) b and c

b) Certain grids may have been much more severely damaged than others. Severely damaged grids may have fewer occupied households.

c) Certain grids may have been much more severely damaged than others. The grids that are selected may not be representative in terms of damage.