Final answer:
The type of sampling used by the research center, as described in the scenario of calling randomly generated telephone numbers, is random sampling. This method ensures that each individual in the larger population has an equal chance to be selected for the poll, thus providing accurate and generalizable results. Option d
Step-by-step explanation:
In the context of the research center's poll, the sampling method used is referred to as random sampling. This is identified by the strategy of randomly generating telephone numbers via computer, which is consistent with the principles of probability sampling.
Within probability sampling, every individual in the population has an equal chance of being included in the sample. This characteristic allows the results of the poll to generalizable to the broader population.
Random sampling is particularly important when getting the right sample is crucial for the accuracy of any poll. It ensures that the opinions of those within the sample reflect the opinions of the entire population being studied. The use of random digit dialing, which includes unlisted and cellular numbers, is one way that researchers mitigate bias and uphold the principles of randomness and representativeness in their sampling methods.
The methods of contacting respondents, such as computer-assisted telephone interviewing (CATI) or other automated systems, play a role in the execution but do not change the random nature of the sample selection if the sample is drawn based on a random digit dialing methodology. option d