An investigator studied the effect of music therapy on pain…

An investigator studied the effect of music therapy on pain ratings among children following a tonsillectomy. She wanted to determine if music therapy was more effective among certain ages of children as compared to other ages. She divided her sample into the following age groups: infants, toddlers, preschool-aged children, school-aged children, and adolescents. In this study, the age groups are:

A researcher wants to study the effect of vitamin D intake o…

A researcher wants to study the effect of vitamin D intake on muscle strength. She randomly assigns subjects to either an experimental group who receive Vitamin D supplementation or a control group who are given a placebo pill that does not contain any active ingredient. She measures subjects’ muscle strength before beginning supplementation and then 6 months after the subjects had been receiving daily supplementation. This is an example of:

Mirbagher-Ajorpaz and colleagues (2011) hypothesized that an…

Mirbagher-Ajorpaz and colleagues (2011) hypothesized that an acupressure intervention would decrease dysmenorrheal among female medical science students. They divided the sample of female medical science students into two groups – one group received the acupressure intervention and the other group did not receive any intervention. What statistical test, from the following list, would be the most appropriate to use to compare the mean dysmenorrhea scores of the intervention and control groups?