1. The research design used in the article "Assessing the Perceived Value of Research Participation" is a survey-based study. This can be determined from the methods section, which outlines the use of a survey to collect data from the participants.

2. The researchers calculated independent-samples t tests to compare the perceived value of research participation among participants with different demographic characteristics, such as gender, education level, and income. They also compared the perceived value of research participation between participants who did and did not receive monetary compensation as part of their participation.

3. The results of the independent-samples t tests showed that there were significant differences in the perceived value of research participation among participants with different demographic characteristics, such as gender, education level, and income. They also found that participants who did not receive monetary compensation for their participation had a significantly lower perceived value of research participation than participants who did receive compensation. Additionally, the researchers found that the perceived value of research participation was higher for participants who received monetary compensation than for those who did not