A researcher was interested in examining the effects of the…

A researcher was interested in examining the effects of the amount of caffeine intake during the day on the quality of participants’ sleep quality of 50 male, sophomores at USF who were randomly selected. Quality of sleep was measured using an actigraphy and amount of caffeine was measured using a self-reported food diary. What effect would using 50 male, sophomores at USF have on internal validity?

If the researcher evaluated the measurement quality of the a…

If the researcher evaluated the measurement quality of the actigraphy by correlating the scores from the actigraphy (score range = 0 to 100 with higher scores representing higher quality) to the scores from the polysomnography (score range = 1.5 to 8.5 with higher scores representing higher quality), the gold standard used to measure sleep quality, what type of measurement evidence is this?

A researcher was interested in examining the effects of the…

A researcher was interested in examining the effects of the amount of caffeine intake during the day on the quality of participants’ sleep quality of 50 male, sophomores at USF who were randomly selected. Quality of sleep was measured using an actigraphy and amount of caffeine was measured using a self-reported food diary. What is the independent variable?