MODERN AUDITING 7th Edition

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SAMPLING DALAM

PENGUJIAN PENGENDALIAN

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AU 350.01 defines audit sampling as the application of an auditprocedure to less than 100% of the items within an accountbalance or class of transactions for the purpose of evaluatingsome characteristics of the balance or class.

Audit sampling is applicable to both tests of controls andsubstantive tests. However, it is not equally applicable to all theauditing procedures that may used in performing these tests.

Konsep DasarKonsep Dasar

When sampling is used in meeting the second and third standardsof fieldwork, it should be recognized that uncertainties may resultfrom factors:

1. Associated directly with the use of sampling (sampling risk) and

2. Unrelated to sampling (nonsampling risk).

Sampling risk relates to the possibility that a properly drawnsample may not be representative of the population.

Risiko SamplingRisiko Sampling

The risk of assessing control risk too low is the risk that theassessed level of control risk based on the sample supports theplanned assessed level of control risk when the true operatingeffectiveness of the control structure policy or procedure, ifknown, would not be considered adequate to support theplanned assessed level.

The risk of assessing control risk too high is the risk that theassessed level of control risk based on the sample does notsupport the planned assessed level of control risk when the trueoperating effectiveness of the control structure policy orprocedure, if known, would be considered adequate to supportthe planned assessed level.

Risiko Sampling dalam Test of ControlRisiko Sampling dalam Test of Control

The risk of incorrect acceptance is the risk that the samplesupports the conclusion that the recorded account balance is notmaterially misstated when it is materially misstated.

The risk of incorrect rejection is the risk that the sample supportsthe conclusion that the recorded account balance is materiallymisstated when it is not materially misstated.

Risiko Sampling dalam Substantive TestRisiko Sampling dalam Substantive Test

Nonsampling risk refers to the portion of the audit risk that is notdue to examining only a portion of the data. Sources ofnonsampling risk include:

1.Human mistakes, such as failing to recognize errors indocuments,

2.Applying auditing procedures inappropriate to the auditobjective,

3.Misinterpreting the results of a sample, and

4.Relying on erroneous information received from anotherparty, such as an erroneous confirmation response.

Risiko NonsamplingRisiko Nonsampling

Pendekatan Sampling - Statistical and NonstatisticsPendekatan Sampling - Statistical and Nonstatistics

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An auditor may use sampling to obtain information about manydifferent characteristics of a population. However, most auditsamples lead either to an estimate of:

1. a deviation rate or

2. a dollar amount.

When statistical sampling is used, these sampling techniques areidentified as attribute sampling and variables sampling,respectively.

Attribute Sampling dan Variable SamplingAttribute Sampling dan Variable Sampling

Attribute Sampling dan Variable SamplingAttribute Sampling dan Variable Sampling

The steps involved in a nonstatistical sampling plan include thefollowing:

1.Determine the audit objectives and procedures to meet theobjectives.

2.Define the population and sampling unit.

3.Specify the control of interest and evidence that the controlwas effective or ineffective.

4.Use professional judgment to determine sample size.

5.Use professional judgment to determine the sample selectionmethod.

6.Apply audit procedures for tests of controls.

7.Evaluate the sample results.

Nonstatistical SamplingNonstatistical Sampling

The steps in a statistical sampling plan for tests of controls are asfollows:

1. Determine the audit objectives.

2. Define the population and sampling unit.

3. Specify the attributes of interest.

4. Determine the sample size.

5. Determine the sample selection method.

6. Execute the sampling plan.

7. Evaluate the sample results.

Statistical SamplingStatistical Sampling

Attributes dalam PengendalianAttributes dalam Pengendalian

Attributes dalam PengendalianAttributes dalam Pengendalian

In order to determine a sample size for each attribute or controlto be tested, the auditor must specify a numerical value for eachof the following factors:

1. Risk of assessing control risk too low

2. Tolerable deviation rate

3. Expected population deviation rate

Sampling StatistikSampling Statistik

Sampling StatistikSampling Statistik

When selecting a random sample, it is possible that the samesampling unit may be drawn more than once. When the duplicatenumber is ignored, the auditor is said to be sampling withoutreplacement.

Statistical tables used by auditors to determine sample size areoften based on sampling with replacement. As a practical matter,however, the auditor usually samples without replacementbecause no new information would be obtained from examiningthe same item twice.

Random SamplingRandom Sampling

Systematic sampling consists of selecting every nth item in thepopulation from one or more random starts. The intervalbetween items is usually referred to as the skip interval.

When a single random start is used, the interval can be calculatedby dividing the population size by the sample size.

A major advantage of systematic selection is that it may take lesstime than other selection methods.

Systematic SamplingSystematic Sampling

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SAMPLING DALAM

PENGUJIAN SUBSTANTIF

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Sampling plans for substantive tests may be designed to:

1.Obtain evidence that an account balance is not materiallymisstated or

2.Make an independent estimate of some amount.

Konsep DasarKonsep Dasar

Audit sampling in substantive tests is subject to both samplingrisk and nonsampling risk. The sampling risks associated withsubstantive tests are:

1.Risk of incorrect acceptance (beta risk) — the risk that thesample supports the conclusion that the recorded accountbalance is not materially misstated when it is materiallymisstated.

2.Risk of incorrect rejection (alpha risk) — the risk that thesample supports the conclusion that the recorded accountbalance is materially misstated when it is not materiallymisstated.

Risiko SamplingRisiko Sampling

The following 2 statistical sampling approaches may be used bythe auditor in substantive tests:

1.Probability-proportional-to -size (PPS) sampling and

2.Classical variables sampling.

Pendekatan SamplingPendekatan Sampling

Pendekatan SamplingPendekatan Sampling

Pendekatan SamplingPendekatan Sampling

Probability-Proportional-to-Size SamplingProbability-Proportional-to-Size Sampling

Probability-Proportional-to-Size SamplingProbability-Proportional-to-Size Sampling

PPS sampling is an approach that uses attribute sampling theoryto express a conclusion in dollar amounts rather than as a rate ofdeviations. This form of sampling may be used in substantivetests of both transactions and balances.

Probability-Proportional-to-Size SamplingProbability-Proportional-to-Size Sampling

Probability-Proportional-to-Size SamplingProbability-Proportional-to-Size Sampling

The steps in a PPS sampling plan are similar to those used inattribute sampling. The steps are:

1. Determine the objectives of the plan

2. Define the population and sampling unit

3. Determine the sample size

4. Determine the sample selection method

5. Execute the sampling plan

6. Evaluate the sample results

Reliability FactorsReliability Factors

Reliability FactorsReliability Factors

Expansion FactorsExpansion Factors