You want to know if part-time employees become more or less happy with their employment over time. thus, you give a questionnaire to 100 new hires and four months later give the same questionnaire to the same employees. what type of research design have you used?

Before they can be published, scientific papers must be peer-reviewed. this means that: a) some other scientific experts read the papers and guarantee that they are true.b) some other scientific experts read the papers and provide quality control by eliminating many mistakes.c) an editor reads the papers, to make sure that all the semicolons are in the correct places.d) everyone in the world is given the opportunity to comment on the papers through a specially maintainedblog.e) government bureaucrats read the papers, to be sure that the papers do not insult the political positions ofthe current officeholders.