Final answer:
Phuong should use experimental research to investigate the effects of radiation on learning because this method allows for establishing cause-and-effect relationships by manipulating the independent variable and observing its direct effects on the dependent variable.
Step-by-step explanation:
To investigate the effects of radiation on learning, Phuong should use experimental research. This is because experimental research allows for the manipulation of the independent variable (in this case, radiation) to see its direct effects on the dependent variable (learning outcomes). Unlike other research methods, an experiment can establish cause-and-effect relationships, which is crucial in understanding the influence of radiation on learning processes. For example, one might create two groups, where one is exposed to radiation and the other is not, and then compare their learning abilities over time to see if there are significant differences attributable to radiation exposure.
Descriptive research merely describes phenomena as they are, without establishing causal links. Correlational research may suggest a relationship between radiation and learning but cannot establish causation. Survey research is generally used to collect self-reported data from participants and would not be suitable for measuring the actual effects of radiation on learning abilities.
As for the types of data collected during experimental research, measuring the energy level of mice treated with a drug is a quantitative observation, while the size of the tumors at the end of a study is quantitative data and would be considered raw data until it is organized into meaningful patterns, at which point it could be referred to as descriptive statistics.