The results show that both stratified random sampling
and systematic sampling are much more effective than
simple random sampling, but systematic sampling is less
precise than stratified random sampling .Systematic
sampling is more precise than simple random sampling
because it picks up any hidden or obvious stratification in
the population. It is clear that the variance of # is less for a
systematic than for a simple random sampling since the list
from which the systematic sample is drawn show a fairly
consistent trend or grouping as the data represent
production during series of time. This means that there may
be a population for which systematic sampling is extremely
precise and others for which it is less precise than simple
random sampling. Therefore the performance of a
systematic sampling in relation to that of stratified or
simple random sampling is mainly dependent on the
properties of the population. On the other hand, a
systematic sample will have the same precision as the
corresponding stratified random sample, with one unit per
stratum, if ' ( ) which is the correlation between the
deviation from the stratum means of pairs of items that are
in the same systematic sample.