 In this video, we provide the solution to question number 16 for practice exam number four for Math 1030, in which case we have a research study that wants to determine whether smell can affect learning or not. So we have participants who have to go through a paper and pencil maze, and the idea is how fast can they do it, okay? And so to conduct the experiment, our participants are going to take, they're going to solve three mazes while wearing a scented mask. And then participants will randomly selected that they do three mazes, or three mazes with the floral mask first, then three with the unscented mask. And then in the other group, randomly assigned participants will wear the unscented mask for three mazes, and then a floral mask for three mazes. And so then the researchers will record the time it took to complete the mazes. And then also participants will be able to take a look at the results of the and then also participants will indicate whether they found the smell positive, negative, or neutral, okay? And so that's the experiment that's going to be conducted. We have to identify any compounding variables that could interfere with this study. So my first thing to note here is that all subjects experienced both treatments, okay? For which case, why could this be a problem here? So we don't have a control group. We don't have a treatment group, but since both people get the experiment there, they both get the treatment and the control, what if that influences what they're doing? I mean, after all, the people we are using in this study can most likely smell. If they can smell the mask. So they'll know when they're doing the experiment, you know, let's put this in a good way. The participants, we'll say the subjects here smell. That'll be a little of our humor here. The subjects smell. They can smell. So they know which mask is the floral mask, okay? As such, the participants know, even, you know, we have randomized it, right? So the order is randomized. So that's a good thing that they did there to try to control some of the compounding variables. Because one of the variables could be that if you do the floral first, then the unscented, that might make you do better or worse than if you do the unscented one than the floral. Because what if the smell has a lingering effect or the lack of smell has a lingering effect? So they did randomize. That's a good thing to try to control it. But my point is still that the participants can know if they're smelling something or not. And because they can see the difference, they potentially could infer a difference that, oh, maybe the smell is better. Maybe the smell makes me do worse. And so they psychologically could be doing something in that regard. The other situation that I want us to be aware of is that the experiment is not blinded. That's really what I'm trying to get here. That the subjects will know which one they're in. They'll know whether they're in the treatment group or the control group. When they're in both of them, their behavior might change because of that. It could be a positive or negative possible effect. People might believe the smell is making it work better because they're part of a study and conversely. But you also have that the researchers themselves don't, the researchers themselves might influence it because they know which is being done at which time. Another situation that's not explained here is how many different mazes are there. We say that they do mazes multiple times. Is it the same maze over and over again? Because that itself might get better over time when they're doing the mazes there. Are they different mazes? And if that's the case, if they're different mazes, are they all the same difficulty? Are the mazes the same difficulty? And so if those mazes are those mazes sufficiently randomized so that the difficulty is inherently the same and the people are getting better because of the smell or because of some other things, these are some confounding factors that could be in play here, some of the limitations of the study. This is definitely not an exhaustive list, but these are some of the ones I'd be concerned with the most.