Final answer:
A researcher would use random assignment to ensure unbiased allocation of participants to experimental conditions. This method prevents biased distribution, unlike random sampling, which is more about selecting participants from a larger population.
Step-by-step explanation:
To assure that participants are assigned to experimental conditions in an unbiased manner, a researcher would use random assignment. This method involves allocating participants to different groups or conditions based purely on chance, thereby minimizing the likelihood of a biased distribution. In contrast, counterbalancing is used to control for the effects of the order in which treatments are administered, and it involves systematically varying the order among participants. Blind sorting is not a commonly used term in this context. A random sample refers to selecting a subset of individuals from a population such that every individual has an equal chance of being chosen, but does not specifically pertain to assignment to conditions once the sample is chosen.