Final answer:
The technique for sampling small, lightweight, non-perishable products is sampling through the mail. This cost-effective method can reach a broad audience. Convenience, cluster, and systematic sampling are other methods that vary in their approach and representation of the population.
Step-by-step explanation:
The common sampling technique for small, lightweight, non-perishable products is sampling through the mail. This method is cost-effective and allows distribution to a wide geographic area without significant shipping costs. It's particularly suitable for products that are easy to package and send, providing the potential for a large and diverse sample.
For instance, when the data is collected by asking the first 111 people who entered a store, the type of sampling used would be convenience sampling. This method is non-random and involves selecting readily available participants; however, it may yield biased results due to not being representative of the entire population.
Other types of sampling mentioned include cluster sampling, where the population is divided into clusters and a random sample is selected from those clusters, and systematic sampling, as demonstrated by a health club asking every tenth customer to complete a survey, which can provide a more evenly distributed sample of the population.