In Exercises 21–28, determine whether the study is an experime...

Question

In Exercises 21–28, determine whether the study is an experiment or an observational study, and then identify a major problem with the study.

Sleep Study When designing the study of a new treatment for insomnia in adults, researchers were criticized because their test subjects consisted of 75 college students. They then expanded the study so that 750 college students were given the treatment.

Accepted Answer

All right, hi everyone. So this question is asking us to determine whether the study mentioned below is an experiment or an observational study, and then identify a major problem with the study. Here it says a research team conducted a study on the effectiveness of a new diet plan for weight loss. Initially, they tested the diet on 50 university students and received criticism from the limited sample. In response, they expanded the study to include 500 university students, all of whom followed the diet for 3 months. And here we also have 4 different answer choices labeled A through D, proposing whether or not the study is an experiment or if it's observational, as well as proposing different problems with the study itself. So first, what defines an experiment? Versus an observational study. Well, for me, the key word here is observational, right? Because recall that in an observational study, the job of the researcher. Is to observe and record accordingly. On the other hand, An experiment involves the manipulation of variables. It could be one variable or it could be multiple. So here, in an experiment, the researcher is deliberately manipulating one or more variables to observe their effects on the outcome that they are studying. Now in an experiment, participants are assigned randomly to each group to ensure fairness. So in this particular case, right? The study itself involves a diet. In other words, it involves a treatment. So researchers are deliberately controlling whether or not each participant. Follows the diet or not. Therefore, it's an experiment and not an observational study. So now, what exactly is the issue with the study itself? Well, first and foremost, the new diet plan. The new diet plan Ostensibly is meant to be used by a greater population, right? But the researchers are only focusing on university students for their data. Now, the problem with this is that it's difficult to generalize this data. If you're focusing on a very specific group of people. In other words, the data that's obtained from university students cannot easily be applied to a greater population because that greater population is going to include people of different ages, different lifestyles, and also different health conditions. So therefore, it's difficult to predict the effects of this diet plan on weight loss. When applying it to a broader population. So therefore, our, our correct answer is going to be option A in the multiple choice. First, because the study is an experiment. And second, because the problem with the study is that the sample consists of only university students, or excuse me, limiting generalizability. And there you have it. So with that being said, thank you so very much for watching, and I hope we found this helpful.

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Key Concepts

Experimental vs. Observational Study

Sample Size and Generalizability

Selection Bias

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