How long is an investigator required to keep consent documents, irb correspondence, and research records?

Which type of learning occurs when you observe how other people act?

Pj conducts an experimental study on the effects of soft music during high stakes science testing. he randomly assigns students at the school. in one condition he does not provide music for testing while in the other group he does provide the music. he administers a pretest at the beginning of the year and a posttest at the end of the year. pj’s design is best described as a: a.static group comparisonb. pretest-posttest control group designc.control-group-time-series designd. nonrandomized control-group pretest-posttest design

Which factor contributed to the rise of african empires such as ghana and mali ? a. their creation and involvement in trade networks b. they focused only on agricultural production. c. they didn’t engage in warfare with other nations d. their geographic location protected them from attacks.