Final answer:
Probability samples ensure all members of a population are equally likely to be included, resulting in excellent external validity due to the representative nature of these samples. The use of random sampling methods helps in creating a representative sample that can generalize findings to the broader population.
Step-by-step explanation:
Studies that use probability samples have excellent external validity because all members of the population are equally likely to be represented in the sample. This representative nature ensures that the sample characteristics closely match the entire population, making findings more generalizable. In probability sampling, methods such as simple random sampling, stratified sampling, cluster sampling, and systematic sampling are employed to guarantee each member in the population has an equal chance of selection.
When random sampling is utilized, it reduces sampling bias and sampling error, thereby increasing the reliability and validity of the study's conclusions. Random sampling methods help ensure a representative sample, which is essential in extending the study's findings to the larger population. It's important to critically analyze statistical data for these qualities to confirm the study's conclusions can be suitably applied in a wider context.