"[NW] Chew Your Food Researchers wanted to determine the assoc...

Question

"[NW] Chew Your Food Researchers wanted to determine the association between number of times one chews food and food consumption. They identified 45 individuals who were 18 to 45 years of age. First, the researchers determined a baseline for number of chews before swallowing food. Next, each participant attended three sessions to eat pizza for lunch until comfortably full by chewing each portion of food 100%, 150%, and 200% of their baseline number of chews before swallowing. Food intake for each of the three chewing treatments was then measured. It was found that food consumption was reduced significantly, by 9.5% and 14.8%, respectively, for the 150% and 200% number of chews compared to the baseline. Source: Yong Zhu and James H. Hollis. “Increasing the Number of Chews before Swallowing Reduces Meal Size in Normal-Weight, Overweight, and Obese Adults,” Journal of the Academy of Nutrition and Dietetics, 11 November 2013.

How is control used in this study?"

How is control used in this study?"

Accepted Answer

Below there. Today we are going to solve the following practice problem together. So first off, let us read the problem and highlight all the key pieces of information that we need to use in order to solve this problem. Researchers wanted to test whether drinking water before meals affects food intake. 50 adults were asked to eat lunch on two separate days, once after drinking 2 cups of water and once without drinking water. The amount of food consumed was measured. How is control used in this study? OK, so it appears for this particular problem we're given a particular scenario which describes a study that is taking place, and in this study we have researchers who wanted to test whether drinking water before meals affects food intake. And they asked 50 adults to participate in a study, and they were asked to eat lunch on two separate days, once after drinking 2 cups of water and once without drinking water, and the amount of food consumed was measured. And based on this information, we are asked to determine how control is used in this study. So that is our final answer that we're ultimately trying to solve for. How is control used in this study? So with that in mind, now that we know what we're solving for, let's read off our multiple choice answers to see what our final answer might be. A is by randomly selecting the type of food participants ate. B is by comparing each participant's intake with and without water. C is by allowing participants to choose how much water to drink. And D is by comparing the food intake of participants with the national average. So, With that in mind, our first step that we need to take is we need to take a moment to recall and identify the purpose of the control. In this particular experiment. So once again, we need to recall what the importance of control is in an experiment. So as you should recall, control is used to minimize the effect of variables other than the independent variables, ensuring that the observed effects are due to the treatment method and nothing else. So with that in mind, our second step now is we need to determine the independent variable for this particular prompt. So as we should recall, the independent variable is whether the participant drank 2 cups of water before the meal or not. So I'll make a note of this as just 2 cups, and we'll know that that meant that they drank 2 cups of water. So once again, the independent variable, which I'll call IV, so this independent variable, once again is whether or not the participant drank 2 cups of water before the meal or not. So with that in mind, our third step now is we now need to identify the control condition. So as we should recall, based on what we were told by the problem itself, the control condition is the meal consumed without drinking water beforehand. So I will say just the meal. is equal to the control condition. So the meal consumed without water, so meal. And I'll just say without water. So without water meal is equal to the control condition. OK, we are on a roll. So once again, the control condition is the meal consumed without drinking water beforehand. So now looking at our 4th step, we now need to explain how the control is implemented in this particular study. So once again, we need to recall a note that each participant serves as their own control by experiencing both conditions, meaning when they have water with their meal or when they don't have water with their meal, which helps to control for individual differences in food intake as a result. So that will mean for our 5th and final step is we need to make our final conclusions. So that means that control is used in this study by having each participant eat lunch both with and without drinking water, which allows the researchers to compare food intake under both conditions within the same individuals. So that will mean that our final answer without a doubt will have to be multiple choice answer letter B, which once again is by comparing each participant's intake with and without water. And that's it. We've officially solved for this problem. Thank you so much for watching. Hopefully that helped, and I can't wait to see you in the next video. Bye.

Key Concepts

Control Group or Baseline Measurement

Within-Subjects Design

Manipulation of Independent Variable

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