2.2. Simple Random or Systematic Sampling

   Two possible objectives for sampling:
    1. Estimate average population density,
    2. Make a map of population density.

   Traditionally, random sampling plans were preferred over systematic sampling
   plans because random sampling helped to avoid subjective selection of sample
   locations. However, systematic sampling has no elements of subjectivity if sample
   location is selected prior to examining the area. For example, there is no
   subjective decisions if we sample every tenth potato plant and count Colorado
   potato beetles.

   Moreover, systematic sampling has an advantage over random sampling if the number
   of samples is large because of more uniform coverage of the entire sampling area.
   It is especially important for making population maps. Random sampling can be
   used if the objective is to estimate the mean population density and the number
   of samples is not large ( EIL, or not suppressed if M < EIL.

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   [6]Alexei Sharov 1/12/96

References

   1. http://alexei.nfshost.com/PopEcol/lec2/geostat.html
   2. http://alexei.nfshost.com/PopEcol/lec2/stratif.html
   3. http://alexei.nfshost.com/PopEcol/lec2/whole.html
   4. http://alexei.nfshost.com/PopEcol/lec2/sampling.html
   5. http://alexei.nfshost.com/PopEcol/lec2/howmany.html
   6. http://alexei.nfshost.com/~sharov/alexei.html