Green Spaces Make Kids Smarter A recent article claims that "Green Spaces Make Kids Smarter." The study described in the article involved 2,623 schoolchildren in Barcelona. The researchers measured the amount of greenery around the children's schools, and then measured the children's working memories and attention spans. The children who had more vegetation around their schools did better on the memory and attention tests.

(a) What are the cases in this study?

(b) What is the explanatory variable?

(c) What is the response variable?

(d) Does the headline imply causation?

(e) Is the study an experiment or an observational study?

(f) Is it appropriate to conclude causation in this case?

(g) Suggest a possible confounding variable, and explain why it meets the requirements of a confounding variable.