What scale of measurement is the variable: The number of days off-work for the 6 months after the end of the treatment?

What effect will increasing the sample size have on the standard error of the mean (sampling error)?

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. Is the sample used in the study a probability sample or a non-probability sample?

Based on the scatterplot, what would you estimate the correlation to be (give a specific number)?

What is a meta-analysis?

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?

The best fitting regression line will

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?

A researcher examined the body mass index (BMI) of 1000 randomly selected undergraduates from USF and found a mean of 18 and a standard deviation of negative 0. 05 (SD=-0.05). What is your interpretation of the standard deviation of -0.05?

Briefly define what is meant by the internal validity of a research design.