An experiment is a primary research method because it involves the manipulation of variables to determine cause-and-effect relationships.

A literature review serves all of the purposes listed: identifying gaps in the research, summarizing existing research, and developing a theoretical framework.

An interview is a qualitative research method because it involves collecting data through open-ended questions and observations.

A hypothesis is a more specific statement that predicts the outcome of a study, while a research question is a broader statement that guides the investigation.

A pilot study serves all of the purposes listed: testing the feasibility of a research study, collecting data for the main study, and developing a research instrument.

Convenience sampling, random sampling, and stratified sampling are all types of sampling methods.

A research proposal serves all of the purposes listed: obtaining funding for a research study, outlining the research design and methods, and demonstrating the researcher's knowledge of the topic.

Experimental design, quasi-experimental design, and non-experimental design are all types of research designs.

A data analysis plan serves all of the purposes listed: describing the methods that will be used to analyze the data, justifying the choice of statistical tests, and ensuring that the data is analyzed in a consistent manner.

Plagiarism, fabrication, and falsification are all types of research misconduct.

A research ethics review board serves all of the purposes listed: protecting the rights and welfare of human subjects, ensuring that research is conducted in a responsible and ethical manner, and reviewing and approving research proposals.

Selection bias, information bias, and confounding bias are all types of research bias.

A research dissemination plan serves all of the purposes listed: describing how the research findings will be shared with the public, identifying potential audiences for the research findings, and developing materials and strategies for disseminating the research findings.

Theoretical impact, practical impact, and policy impact are all types of research impact.

A research portfolio serves all of the purposes listed: showcasing the researcher's accomplishments, documenting the researcher's research activities, and helping the researcher track their progress.