Questions: A sample that consists of a random selection of groups or units is called a sample.

    In statistics, sampling methods are crucial for collecting subsets of data from a population. 
    The main goal is to obtain a sample that accurately represents the larger population. 
    Sampling methods can be broadly categorized into probability and non-probability sampling. 
    In probability sampling, every member of the population has a known, non-zero chance of being selected. 
    This category includes simple random sampling, systematic sampling, stratified sampling, and cluster sampling. 
    Among these, cluster sampling is unique as it involves selecting entire groups or clusters of individuals randomly, 
    rather than selecting individuals directly. This method is particularly useful when it's difficult or impractical 
    to compile an exhaustive list of the individuals within the target population but relatively easy to compile the list of groups.
    

    ### Step 2: Identifying Key Characteristics
    The key characteristic of the sampling method in question is the random selection of groups or units, 
    rather than individuals. This method is distinguished by its approach to select entire clusters at random, 
    and then including all members of these clusters in the sample. This approach is particularly efficient 
    when the population is naturally divided into groups, and when these groups are internally homogeneous 
    but heterogeneous between each other. This characteristic aligns with the concept of cluster sampling.
    

    ### Step 3: Applying the Correct Term
    Based on the description provided, the correct term for the sampling method is "cluster". 
    This term is applied when the sample consists of a random selection of groups or units, 
    where each member of the selected group is included in the sample. This method assumes that 
    the selection process is truly random, ensuring every possible group or unit has an equal chance 
    of being selected. It also assumes homogeneity within clusters to ensure the sample is representative 
    of the larger population. This method is practical when it is feasible to identify and select entire 
    groups or units, making "cluster" the appropriate term for the described sampling method.
    

    ### Final Answer

    The correct terminology for a sampling method where the sample consists of a random selection of groups or units is "cluster". 
    This method, known as cluster sampling, is characterized by its approach to select entire clusters or groups randomly, 
    and including all members of these clusters in the sample. It relies on the assumptions of randomness, 
    homogeneity within clusters, and the feasibility of group selection to ensure the sample is representative 
    of the larger population.