An observational study conducted in inner-city Boston approximately four years ago demonstrated that high-school students who consumed more than five cans of non-diet soda every week were between 9 and 15-percent likelier to engage in an aggressive act compared with counterparts who drank less non- diet soda. Based on this evidence, we can reliably conclude that A. engaging in aggressive acts must have caused students to drink non-diet soda
B. students who drank less non-diet soda were generally less likely to engage in aggressive acts
C. a third variable, such as students' home environment, must have caused students to both drink more non-diet soda and engage in aggressive acts
D. drinking non-diet soda must have caused students to engage in aggressive acts SALO

C. a third variable, such as students' home environment, must have caused students to both drink more non-diet soda and engage in aggressive acts

Explanation:

From the question, we are informed about An observational study that was conducted in inner-city Boston approximately four years ago demonstrated that high-school students who consumed more than five cans of non-diet soda every week were between 9 and 15-percent likelier to engage in an aggressive act compared with counterparts who drank less non- diet soda. In this case, we can reliably conclude that a third variable, such as students' home environment, must have caused students to both drink more non-diet soda and engage in aggressive acts.

Observational studies can be regarded as studies whereby

researchers make observation about different effect of factors such as

risk factor, home, as well as environment and diagnostic test that affects the experiment. In observational studies Variables are very crucial, A variable can be anything that that is liable to change, it can change and it can be changed as well. They are factors which the observer can manipulate or control for when carrying out experiments.

sounds good to me mate!