Explain the relationship between the alpha level and Type 1 error.
Explain the relationship between the alpha level, or significance level and Type 1 error.
• A researcher is studying the effects of yoga on depression. Participants are randomly assigned to one of two groups: yoga and medication, which is the experimental group; or support group and medication, which is the control group. What is the null hypothesis? What is the research hypothesis? (2 points)
• In the scenario described in the previous question, the researcher implements two programs simultaneously: a 6-week yoga program coupled with medication management and a 6-week support group program coupled with medication management. At the end of the 6 weeks, participants complete a questionnaire measuring depression. The researcher compares the mean score of the experimental group with the mean score of the control group. What statistical test would be most appropriate for this purpose? Explain your response. (2 points)
• In the scenario described in the previous questions, the researcher predicted that participants in the experimental group—yoga plus medication—would score significantly lower on measures of depression than would participants in the control group—support group plus medication. True or false: A two-tailed test of significance is most appropriate in this case. Explain your response. (1 point)
• Explain the relationship between the alpha level, or significance level and Type 1 error. (2 points)
• A researcher is studying the effects of sex—male and female—and dietary sugar on energy level. Male and female participants agree to follow either a high sugar or low sugar diet for 8 weeks. The researcher asks the participants to complete a number of questionnaires, including one assessing energy level, before and after the program. The researcher is interested in determining whether a high or low sugar diet affects reported energy levels differently for men and women. At the end of the program, the researcher examines scores on the energy level scale for the following groups:
o Men – low sugar diet o Men – high sugar diet o Women – low sugar diet o Women – high sugar diet
• What statistic could the researcher use to assess the data? (1 point)
• Use the information presented in the previous question to discuss one possible main effect that might emerge from the analysis and one possible interaction that might emerge. (2 points)