营销调研sling(编辑修改稿)

营销调研sling(编辑修改稿)内容摘要：

elect every 30th (6000 divided by 200) person from the list. In practice, we would randomly select a number between 1 and 30 to act as our starting point. Stratified Sampling Stratified sampling is a variant on simple random Used when there are a number of distinct subgroups, within each of which it is required that there is full representation. A stratified sample is constructed by classifying the population in subpopulations (or strata), based on some wellknown characteristics of the population, such as age, gender or socioeconomic status. The selection of elements is then made separately from within each strata, usually by random or systematic sampling methods Cluster or Multistage Sampling Is particularly useful in situations for which no list of the elements within a population is available and therefore cannot be selected directly. As this form of sampling is conducted by randomly selecting subgroups of the population, possibly in several stages, it should produce results equivalent to a simple random sample Cluster samples are generally used if: No list of the population exists. Welldefined clusters, which will often be geographic areas,exist. A reasonable estimate of the number of elements in each level of clustering can be made. Often the total sample size must be fairly large to enable cluster sampling to be used eff。