Which of the following is an example of a null hypothesis?

A researcher conducted a study examining hearing tests of 100 children. She reported that subjects ranged from 3-9 years old (mean = 6 years, SD = 1 year). How many standard deviations below the mean was the youngest participant?

Using volunteers as subjects in a study,

An investigator collects data that are normally distributed with a mean score of 50 and a standard deviation of 10. Approximately 95% of the scores would fall between which two numbers?

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 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?

Eating 3 servings of green beans per week decreases a woman’s risk of breast cancer. This statement is an example of a:

A researcher studied the difference in pretest and posttest scores in a group of subjects. Using the standard 0.05 level of significance and based on the following SPSS output, which conclusion would you make?

Which of the following statements about informed consent is FALSE?

A researcher studied how much time parents spent playing with their children with disabilities. The dependent variable was amount of time playing. The independent variables were disability status of the child (no disability, physical disability, or mental disability) and the gender of the parent (male or female). After collecting data, the researcher ran a Two-way ANOVA. According to the following SPSS output, how would you describe the interaction effect between disability status and gender?