Final answer:
The validity of internet-based research can be established through comparison with traditional methods, increased sample sizes, random participant assignments, and the inclusion of varied participant demographics. Validity ensures the research measures what it intends to, while carefully designed experiments can provide causal evidence by controlling biases and ensuring consistent treatment across groups.
Step-by-step explanation:
According to Krantz and Dalal (2000), the validity of research conducted on the Internet can be established by comparing it to traditional research methods, increasing sample size, random assignment of participants, and using non-psychology majors as participants. In sociological research, validity is crucial to ensure the study measures what it's designed to measure, and reliability increases the likelihood that results can be replicated. The use of convenience samples, like psychology students, can have implications such as a potential lack of generalizability to the broader population.
The greatest strength of experiments in research is the ability to make causal statements due to the methodology of random selection, random assignment, and designs that limit biases. These elements contribute to the similarity in group composition and treatment, implying that differences observed are due to the independent variable alone. Field research methods, which include experiments, surveys, participant observation, among others, have their own sets of advantages and disadvantages. Such methods should be chosen based on the research question and designed to handle both predicted and unpredicted data effectively.