1. Statistical sampling in Audit for the NSO Comptroller & Auditor General Of India1 Stratification & Cluster Sampling

2. Statistical sampling in Audit for the NSO Comptroller & Auditor General Of India2 Stratified Random Sampling  Population is partitioned into smaller sub- population,called strata.  These strata should be mutually exclusive and collectively exhaustive & homogeneous according to some characteristics.  Then a sample of n i = n(N i /N) will be chosen at random from i th strata. I = 1,2,3,….k,Where k is the no. of strata.(Proportional allocation)  This is used to increase precision without increasing cost.

3. Statistical sampling in Audit for the NSO Comptroller & Auditor General Of India3 Where, SDi = Standard Deviation of the i th stratum. Ni = No. of items /transactions in i th stratum. = Acceptable margin of error for mean. Z r = Standard Normal value for the desired confidence level. n i = optimum sample size of ith strata. Optimum allocation in strata

4. Statistical sampling in Audit for the NSO Comptroller & Auditor General Of India4 Cluster Sampling  It is used whenever the population is homogeneous but can be partitioned & for practical convenience  The target population is first divided into mutually exclusive and collectively exhaustive subpopulations.  Then a random sample of cluster is selected by SRS.Each selected cluster is either all the units are included or a sample of elements is drawn probabilistically.

5. Statistical sampling in Audit for the NSO Comptroller & Auditor General Of India5  In cluster sampling only a cluster is chosen  Elements within a cluster should be as heterogeneous as possible  It is operationally convenient and possible reduction of costs  In stratified sampling all the strata are chosen for further sampling.  Elements within a strata should be as homogeneous as possible.  It increase the precision of the estimates without increasing costs Stratified Vs. Cluster Sampling

6. Statistical sampling in Audit for the NSO Comptroller & Auditor General Of India6