Question

identify the sampling techniques used, and discuss potential sources of bias (if any). explain. after a earthquake, a disaster area is divided into 250 equal grids. twenty 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. 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 divided 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 divided 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. certain grids may have been much more severely damaged than others. the grids that are selected may not be representative in terms of damage b. certain grids may have been much more severely damaged than others. severely damaged grids may have fewer occupied households. c. the sample only consists of grids that are easy to get. these grids may not be representative of the population. d. there are no potential sources of bias.

Explanation:

1. Sampling technique: In cluster - sampling, the population is divided into clusters (here, the disaster area is divided into grids), and some of these clusters are selected, and all elements within the selected clusters are included in the sample. This matches the described sampling method.
2. Sources of bias:

• Option A: If some grids are more severely damaged than others and the selected grids are not representative in terms of damage, it can lead to bias as the needs of residents in different - damage levels may vary.
• Option B: Severely damaged grids having fewer occupied households can also introduce bias as the sample may not fully represent the overall population of the disaster - area residents.
• Option C: If the sample consists only of easily - accessible grids, these grids may not be representative of the entire disaster - area population.

Answer:

What type of sampling is used?
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

What potential sources of bias are present, if any?
A. Certain grids may have been much more severely damaged than others. The grids that are selected may not be representative in terms of damage
B. Certain grids may have been much more severely damaged than others. Severely damaged grids may have fewer occupied households
C. The sample only consists of grids that are easy to get. These grids may not be representative of the population