Consider each of the following scenarios and identify the independent, dependent, and attribute variables. Also name one extraneous variable that should be controlled by the researcher."A group of experienced and “fresh” teachers (with 10 plus years' and less than two years' experience, respectively) attended 10 workshop sessions in stress reduction techniques (the treatment). A randomized group of experienced and fresh teachers functioned as a control group. The groups were then compared on a measure of stress (blood pressure). It was found that the treatment was linked to lower levels of stress, with fresh teachers showing a greater effect."

The independent variable in this study is the stress-reduction class, and the dependent variable is blood pressure, a measure of stress. Attribute variables are qualities of the participants outside of the researcher's control like age, gender, race, socioeconomic status, etc. Extraneous variables are other things that could impact blood pressure like diet, exercise, and smoking habits. These cannot be controlled perfectly, but the researcher should place some parameters on them in order to obtain more precise results.

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This study wants to determine the effect of a ten-week stress-reduction course on teachers, using blood pressure as a measure of stress. It also wants to see if the stress reduction course has a different effect on less experienced versus more experienced teachers. Remember that in research, the independent variable...

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This study wants to determine the effect of a ten-week stress-reduction course on teachers, using blood pressure as a measure of stress. It also wants to see if the stress reduction course has a different effect on less experienced versus more experienced teachers. Remember that in research, the independent variable is what the researcher manipulates, and the dependent variable is the outcome believed to have some relationship with the independent variable. In this case, the independent variable is the ten-week stress-reduction course, and the dependent variable is the teacher's blood pressure. The researchers want to see if those introduced to the stress reduction course have lower blood pressure (dependent variable) than teachers who do not take the course (control group).

Attribute variables are things that the researchers can not manipulate but may still have an affect on outcomes. Examples of attribute variables in this study include age, gender, ethnicity, and socioeconomic status. These qualities are inherent to the study participants, so the researcher cannot manipulate them unless they further narrow their pool of participants. However, all of these attributes could still have an impact on blood pressure and/or stress levels, so the researchers will never be able to say with 100% certainty that this stress-reduction course lowers blood pressure in all teachers. This doesn't mean that the researchers did anything wrong per se; working with human subjects will always be an imperfect science because there are so many variables that cannot be controlled perfectly. However, in their report on the study, they should probably include the demographic information of their sample to paint a picture of the population they worked with. One attribute variable they do account for somewhat is age. They compare results between experienced and less experienced teachers, and with a few exceptions, we can probably assume that the more experienced teachers are older. Splitting the study into these groups helped researchers determine that in their specific sample, the treatment had a greater impact on the less experienced (and presumably younger) teachers.

Extraneous variables are other things that might have an impact on the dependent variable; in fact, attribute variables are a type of extraneous variable. Like the attributes discussed above, there are plenty of things besides stress that could impact blood pressure. Examples include lifestyle choices like diet, alcohol consumption, exercise habits, and smoking. It would be hard to control all of these variables, especially exercise habits. However, to get more accurate results, the researchers should probably limit the study to either smokers or non-smokers. Additionally, they could require that participants refrain from eating, drinking alcohol, or exercising twelve hours before their blood pressure is taken, although the effects of these variables on blood pressure are the result of more long-term habits. Since blood pressure is such an imprecise measure of stress due to these confounding variables, the researchers might want to consider using another method, such as a survey or interview. Of course, these outcomes can also be manipulated by researcher and participant bias, and the statistical processes used by researchers are supposed to determine the significance of their results to account for confounding variables. Ideally, the researchers would have both qualitative and quantitative data from a variety of studies before making firm conclusions about the efficacy of their stress-reduction program.

Finally, the scenario above does not clarify whether the researchers took the participants' blood pressure before the study for a baseline measurement. This is essential because the researchers do not only want to compare results between the control and the experimental groups, but within the experimental group before and after the stress-reduction class.

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