00365nam a2200133 a 450000500170000002000150001708200160003210000230004824500240007125000120009526000380010730000260014549000600017120251203110749.0  a9971512718  a519.52bCOC  aCochran, William G  aSampling techniques  a3rd ed.  aCanadabJohn Wiley & Sons.,c1999  axvi, 428p.c24 cm. PB  aWiley series in Probability and Mathematical Statistics