Final answer:
A valid scientific investigation requires reliable data collection methods and appropriate data type selection to answer scientific questions effectively.
Step-by-step explanation:
To conduct a valid investigation in science, a student should consider several factors, among which two are fundamental: reliable data collection methods and appropriate data type selection. First, the student must utilize reliable data collection methods that are repeatable and provide accurate measurements. These methods should account for potential variables and biases that could skew the results. Second, the student should justify the selection of data types that are needed to answer the scientific question at hand. Whether it is quantitative or qualitative data, this choice directly impacts the relevance and rigour of the conclusions drawn from the research.