Final answer:
The issue with the sample size in the Zhou study lies in potential non-representativeness due to factors like volunteer bias, confounding variables, and low response rates, which can compromise the study's validity and reliability of its conclusions.
Step-by-step explanation:
The issue with the sample size in the Zhou study relates to the representativeness and validity of the study's conclusions. A concern mentioned is whether a study sample of 1,000 is reliable for a population of 5,000. Generally, a sample size of 1,000 could be considered sufficient for a population of 5,000, given that the sample is randomly selected and the population is homogenous. However, if the sample is not representative due to factors such as volunteer bias or confounding variables, which seems to be the case in the Zhou study, then the validity of the conclusions can be compromised. Additionally, when self-selected samples are used, such as the case with 500 volunteers for a population of 2,500, the reliability of the measure is reduced because it may not accurately reflect the entire population's characteristics.
Another problem with samples is evident when response rates are low, as mentioned in a scholarly article about response rates. A low response rate, such as 11 participants responding out of a larger pool, can lead to concerns about the validity of the estimates drawn from such research. Similarly, in the Zhou study, the fact that participants using the software were also a part of an exercise program introduces a confounding variable, making it challenging to determine whether the software alone was responsible for any improvements noted. Such confounding can lead to erroneous conclusions, thus questioning the reliability of the study's findings.