Final answer:
Testing an idea to determine its effectiveness requires having a specific goal that provides measurable results, which can affirm or refute the hypothesis being tested through controlled experiments.
Step-by-step explanation:
Testing an idea to see if it is effective involves a process known as hypothesis testing, which is a fundamental aspect of the scientific method. The correct answer to the question is: 'a. a specific goal against which to measure the outcome.' To test a hypothesis, researchers must have a specific goal or objective which can provide measurable results that determine whether the idea is supported or not. These results should ideally give clear yes or no answers regarding the hypothesis being tested.
In the context of a scientific experiment, the goal might be to ascertain the effectiveness of a new medicine. Researchers would conduct controlled experiments, comparing the outcomes of an experimental group with a treatment against those of a control group with no treatment, to isolate the effects of the medicine. This process allows researchers to determine the cause-and-effect relationships and to see if any observed effects are due to the treatment or just by chance.