(1) What Is the Independent Variable in This Study?
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Class Exercise #1
Brusser and Janosy wanted to test the effectiveness of a new relaxation/biofeedback intervention on menopausal symptoms. They invited women who presented themselves in an outpatient clinic with complaints of sever hot flashes to participate in the study of the experimental treatment. These 30 women were asked to record, every day for 2 weeks before their treatment, the frequency and duration of their hot flashes. The intervention involved five 1 hour sessions over a period of a week. Then, for the 2 weeks after the treatment, the women were asked to record their hot flashes again every day. At the end of the study, Brusser and Janosy found that both the frequency and average duration of the hot flashes had been significantly reduced in this sample of 30 women. They concluded that their intervention was an effective alternative to estrogen replacement therapy in treating menopausal hot flashes.
Exercise Questions
(1) What is the independent variable in this study?
(2) What is the dependent variable in this study?
(3) Was there random assignment in this study?
(4) Is the design experimental, quasi-experimental, pre-experimental or non- experimental?
(5) What is the specific name of design used in this study?
(6) Is the study design within-subjects or between-subjects?
(7) Was selection a possible threat to the internal validity of this study?
(8) Was history a possible threat to the internal validity of this study?
(9) Was mortality a possible threat to the internal validity of the study?
(10) Would it be possible to address the same research question with a stronger research design? Class Exercise #2
Brady hypothesized that the absence of socioemotional supports among the elderly results in a high level of chronic health problems and low morale. She tested this hypothesis by interviewing s sample of 250 residents of one community who were ages 65 years and older. The participants were randomly selected from a list of town residents. Brady asked a series of questions about the availability of socioemotional supports (ie., whether the participants lived with any kin, whether they had any living children who resided within 30 minutes away, etc…). Based on responses to the various questions on social support, participants were classified in one of three groups: low social support, moderate support, and high social support. In a 6 month follow-up interview, Brady collected information from 214 participants about the frequency and intensity of the respondent’s illnesses in the preceding 6 months, their hospitalization record, and their overall satisfaction with life. The data analysis reveled that participants in the low- support group had significantly more health problems and hospitalizations and lower life satisfaction ratings than those in the other two groups. Brady concluded that the availability of social supports resulted in better physical and mental adjustment to old age.
Exercise Questions
(1) What is the independent variable in this study?
(2) What is the dependent variable in this study?
(3) Is the design experimental, quasi-experimental, pre-experimental or non- experimental?
(4) Is the study design within-subjects or between-subjects?
(5) Is the study design cross-sectional or longitudinal?
(6) Is the study design prospective or retrospective/
(7) Was random assignment used to control extraneous variables?
(8) Was matching used to control extraneous variables?
(9) Was selection a possible threat to the internal validity of this study?
(10) Was there attrition in the study?
(11) Would it be possible to address the same research question with an experimental design?