I found this I don’t know if it helps
Answer:
Although unified politically, the United States was hurt by sectionalism, or competition among sections or regions of the country. In the early 1800s three major sections emerged: the industrial Northeast, the agricultural South, and the largely frontier West.
Explanation:
George W. Bush, and George H. W. Bush
The research error described above is an example of selection bias.
Selection bias takes place when, from a population of interest, a group of individuals is selected in order to construct a sample but without a proper randomization. The result is a sample which is not representative of the underlying population.
According to the example, the target population of the research comprises all students but the sample only includes boys. Hence, selection has not been random because it followed a gender criteria, and the results obtained using it cannot be applicable to the whole population because they are affected by a selection bias.
