Professor medina studies the relationship between working in confined spaces and mood. she has read about other studies in the scientific literature, with findings similar to hers. although she can try to explain her observations, she would still need to to identify causal relationships.

Although she can try to explain her observations, she would still need to "conduct a controlled experiment " to identify causal relationships.

A controlled experiment is an exceptionally centered method for gathering information and is particularly helpful for deciding examples of circumstances and end results. This kind of experiment is utilized in a wide assortment of fields, including medicinal, mental, and sociological research.  

To direct a controlled experiment, two groups are required:  an experimental group and a control group.  

The experimental group is a gathering of people that are presented to the factor being analyzed. The control group, then again, isn't presented to the factor. It is basic that all other outer impacts are held consistent. That is, each other factor or impact in the circumstance needs to remain precisely the same between the experimental group and the control group. The main thing that is diverse between the two gatherings is the factor being inquired about.

marginal cost is a microeconomic measure that us to evaluate the extent to which the level of production of a good is sustainable in accounting, that is, to how many quantities the company plans to profit from the production of the good.

the concept of marginal cost is simple, it means the cost of producing one more item. for example, in the case of pies, the marginal cost is the cost of producing one more pie than those that have already been produced.

it is important to understand that productive activity influences marginal cost. the marginal cost of some goods can be very high, while others may be insignificant. for example, the marginal cost of producing an extra plane is very high. already the marginal cost of a water company to provide 1l more water is derisory.

in the case of pies, the cost involves the inputs, the labor and the fixed cost, which involves the fixed space of the bakery. the level of production initially has the marginal cost decreasing because there is space and manpower available. however, to produce more you have to hire more workers and buy more inputs. if physical space is limited, workers will conflict with places, inputs and their productivity will decrease, meaning there is an optimum point of production for each level of space and manpower. from this point on, the productivity of the workers will be getting smaller because of lack of space, so that the marginal cost of producing one more pie will be increasing. so, although you have not posted the chart, but if you have the answer, you can see that my explanation goes according to the marginal cost curve that will increase from the 4th pie, answer (c).

what words? are you talking about to complet what sentence