Sequential Samplin

The previous  has shown  that the sampling  units  were drawn  prior  to the drawing of the actual   sample  and has  a fixed  size. But the  sequential  sampling  known  as  sampling analysis differs  from  the previous  samples in the sense that it  does not make  an advance determination  of the sample size. In  this case the  researcher  obtains measurements on  one  unit  or the population at a single time. A group  of population  units is  also measured  at a time. The measurement of each group  are cumulated. With the  probable error and the cumulated results the size of the  sample can  be decided. If  the error is too  large  the study  of additional groups  continues until  the standard  error is reduced  to a minimum level.

The  sample  size may  vary  according  to the need  of the  management and standard error. It is  not fixed in test the  hypotheses sequential  sampling  reduces the required  sample size as compared to the fixed sampling. When the sequential  sampling  is applied  the survey costs  may be reduced. The utility of  sequential sampling in marketing is not very useful because there is need of a randomly selected  sample or  cross section study. No small  group  of sample  will  be sufficient. There may be  need of  additional groups of samples to  reduce standard  error which may  involves  more cost. By the  time the  nest sample  is taken  into study  the report  of the  previous study  may be outdated. Considering the  utility of the  continuing  sampling the sequential  sample  is utilized in  the marketing  study.