Learned Previously About Assignment Help: How to Answer This Question

Understanding this question requires applying core subject principles.

What This Question Is About

This question relates to learned previously about and requires a structured academic response.

How to Approach This Question

Break the problem into smaller parts and analyze each logically.

Key Explanation

This topic involves learned previously about. A strong answer should include explanation, application, and examples.

Original Question

We learned previously about a study in which volunteers (all around 30 years of age and from the Chicago area) wore light sensors to measure their exposure to sunshine.1 It was found that those who experienced more sunshine had lower body mass indexes (BMIs). The study was not an experiment, so no conclusions about cause and effect could be made. We have already attempted to design an experiment that would determine if more sunlight exposure could cause a reduction in average BMI. The best way that we can determine if sunlight is responsible for lowering average BMI is to gather volunteers and randomly divide them into various treatment groups that are similar in composition. Let’s assume that all participants wear sunscreen to protect their skin. Part A: Suppose one group gets 2 hours of sunshine per day, another group gets 1 hour of sunshine per day, and a third group gets no sunshine each day. Suppose also that the group that gets 2 hours of sunshine each day has the biggest decrease in average BMI. Can you think of alternate explanations for the drop in BMI? When people are outside, they are naturally more active. There is no alternate explanation. It is possible that the people who were assigned to spend 2 hours in the sun had lower BMIs from the start. It is possible that the group members who do not spend time in the sun had lower BMIs from the start. Part B: If one of the above is an alternate explanation for the reduced BMI in the group that spends the most time in the sun, how can we control this? Ensure that all groups spend the same amount of time exercising. There is no alternate explanation, so there is no need to control it. Make sure that the groups have people who are of similar health. Make sure that the average BMI is the same in both groups before beginning the study. Part C: The way that the study is described indicates that the groups are composed of volunteers. Is this a problem for this study? No, because experiments do not require representative samples–just similar treatment groups. Yes, because experimental studies should use representative samples. No, because the volunteers are all similar in age. Yes, because volunteers are, by nature, different from most other people Part D: Researchers have decided to make the groups as similar as possible by ensuring that they follow diets that limit calories and that all groups exercise similarly. Have they done all they could to limit BMI variability within the groups? Yes, all groups are getting similar amounts of exercise. No, aside from ensuring that all volunteers are around 30 years of age, there is no reason to think that there would not be other variability due to things such as gender, weight, etc. No, it is possible that people with lower BMIs all end up together in one group. Yes, all groups are eating diets with restricted calories. Part E: What is the value of limiting variability within each group? To make changes in BMI easier to identify To minimize confounding variables To control the placebo effect Part F: One way to limit variability in the experiment would be to implement blocking. Which of the following blocking schemes would not help to accomplish this? Create blocks by age. Create blocks as treatment and control groups. Create blocks by gender Create blocks by BMI (such as low, medium, and high BMI blocks). Part G: Can we implement blinding with the volunteers, and, if so, how? Yes, volunteers should not know what treatment they are receiving. No, it is not possible to hide the treatment from the volunteers Yes, volunteers who stay indoors can be provided with artificial lighting so that their experience is similar to those who go outside. No, volunteers will know that they are in the study. Part H: Can we implement blinding among those who interact with the volunteers? No, but this would not help control confounding anyway. Yes, and this would help control confounding variables. No, but it does not matter because the placebo effect would not be a problem anyway. Yes, but this would be of no value since the volunteers already know about the treatment. Part I: What is one disadvantage to blocking? It can end up dividing the volunteers into so many groups that there are too few volunteers in each group. It can introduce confounding variables. It makes the experiment less sensitive to changes in average BMI. [1] Aubrey, A. (2014, April 3). Good day sunshine: Could morning light help keep us lean? NPR. Retrieved November 19, 2014, http://www.npr.org/blogs/health/2014/04/03/298358419/good-day-sunshine-could-morning-light-help-keep-us-lean..

******CLICK ORDER NOW BELOW AND OUR WRITERS WILL WRITE AN ANSWER TO THIS ASSIGNMENT OR ANY OTHER ASSIGNMENT, DISCUSSION, ESSAY, HOMEWORK OR QUESTION YOU MAY HAVE. OUR PAPERS ARE PLAGIARISM FREE*******."