Final answer:
Iannello et al.'s investigation likely included a mix of sociological research methods tailored to their specific research questions, considering both ethical constraints and the importance of statistical analysis.
Step-by-step explanation:
When Iannello et al. investigated differences, they employed various sociological research methods, which likely included controlled experiments, observational studies, hypothesis development, or simple observations. The research design is crucial in organizing and implementing these methods to ensure a study can withstand scrutiny. Choosing between methods like surveys, ethnographic research, or experiments depends on the research questions posed. Notably, ethics limit certain experimental designs, particularly those that can harm participants, indicating a need for careful planning during the research design phase to respect these constraints. Once data is collected, it's typically subjected to rigorous statistical analysis to determine the significance of the findings, ensuring that any difference observed is not due to chance.