Page 38 - Agricultural Census 2000 NWFP Vol II Part 1
P. 38

In  general  terms  the  quality  of                   items,  their  sampling  errors  are
            the  census data  may be  adjudged  on                        brought  on  comparable  terms
            the      criterion     of     (1)     internal                by      expressing        them       as
            consistencies  and  reasonableness;                           percentages  of relevant  sample
            and  (2)  by  comparison  with  other                         estimates.         The       resultant
            corresponding  series.  The  estimates                        measure  is  designated  as  co-
            presented  in  this report were checked                       efficient  of  variation  which  can
            for  quality for  technical  terms  as  well                  be  worked  out  directly  from  the
            as for general terms.                                         census        data.       For       the
                                                                          Agricultural  Census  2000  co-
              (1)  Sampling Error                                         efficients of variation  have been
                                                                          worked  out  for  a  number  of
                    Sampling  error is  a  measure to                     important  items  and  given  in  ·
                    determine       the     precIsIon      /              Appendix-Ill  for  enlighting  the
                    consistency  of  the  sample                          data  users  about  accuracy  of
                    results,  i.e.  the  closeness  of                    the  concerned  estimate(s).  The
                    sample       results      to    those                 formula  used  for  estimating
                    obtained      through       complete  ,               relative    variance       (R.V.)     is
                    count  conducted  with  exactly                       described  in  the  succeeding
                    similar       arrangements           of               paragraphs.
                    training,              enumeration,
                    supervision,  processing,  etc.  In              a)  Relative         Variance         (R.V.)
                    other  words,  sampling  error  is
                                                                          Estimates at Sub-division Level
                    not  'error',  as  the  word  error
                    portrays,  but  is  the  probable                    At  the  sub-division  level,  R.V.
                    difference        between          the
                                                                          can  be  estimated  simply by first
                    population      mean       and     the
                                                                          raising  the  sample  observations             .  .
                    sample  mean.  Suppose,  if  a
                                                                          of each  patwar circle to  stratum
                    number  of       estimates  for  an
                                                                          level  using  the  overall  raising
                    item  are  developed  from  all                      factor  for  each  holding  but
                    possible  samples  of same  size
                                                                          excluding  all  National  Certainty
                    drawn  with  simirar  procedure
                                                                          Holdings  (NCHs),          and  then
                    from  a  population,,  their  mean
                                                                         summing        up  to      obtain     an
                   would  be  equal  to  the  mean
                                                                         estimate  for  each  half  stratum
                    based  upon  complete  count                          as under:-
                    and  their  dispersion  about  that
                    mean,  measured  in  terms  of
                                                                  A         r1   qi   (Nk -  N'k - N;'k)   Yh'1ikl'"
                   variance,  is  called  sampling
                                                                  yh'1  =  L [ L  L
                   variance.  The  square  root  of
                                                                                 k   I"'                  ph'1jk
                    sampling  variance  is  known as
                    sampling error.
                                                                                Qj    N"k    yh'1jkl"
                                                                        +      I    I                 ]
                   Further,  to compare precision  of
                                                                                k     I"    ph'1j  ·
                   sample  estimates  of  different

                                                           ( XXXVI)
   33   34   35   36   37   38   39   40   41   42   43