What is the role of sample size in research studies?

The role of sample size in research studies is critical, particularly in terms of reliability and validity. A larger sample size enhances the accuracy of the results by providing a better representation of the population being studied. This improvement in representation allows researchers to draw more generalizable conclusions from their findings.

When the sample size is increased, the variability of the sample means becomes smaller due to the law of large numbers. This means that the findings are less likely to be due to random chance, which, in turn, increases the reliability of the conclusions drawn from the research. In terms of validity, a larger sample size helps ensure that the results reflect the true characteristics of the population, reducing the likelihood of biases that can occur with smaller samples. Therefore, a larger sample size leads to a more robust and trustworthy research outcome.

The other choices do not accurately reflect the implications of sample size in research, as increasing the margin of error contradicts the purpose of larger samples, and quicker results and decreased costs are not inherently linked to sample size.