<standard>
  <front> 
    <iso-meta>
      <title-wrap xml:lang='en'>
        <main>Sampling procedures for inspection by variables</main>
        <compl>General specification for single sampling plans 
          indexed by acceptance quality limit (AQL) 
          for lot-by-lot inspection 
          of independent quality characteristics</compl>
        <full>
          Sampling procedures for inspection by variables &mdash;
          Part 2:
          General specification for single sampling plans 
          indexed by acceptance quality limit (AQL)
          for lot-by-lot inspection
          of independent quality characteristics</full>
      </title-wrap>
      <title-wrap xml:lang='fr'>
        <main>R&egrave;gles d'&eacute;chantillonage 
          pour les contr&ocirc;les par mesures</main>
        <compl>Spécification générale pour les plan
	  d'échantillonage simples, indexés d'après la
	  limite d'acceptation de qualité (LAQ), pour les
	  contr&ocirc;les lot part lot des caractéristiques
	  de qualité indépendantes</compl>
        <full>
          R&egrave;gles d'&eacute;chantillonage 
          pour les contr&ocirc;les par mesures &mdash;
          Partie 2:
          Spécification générale pour les plan d'échantillonage simples, 
          indexés d'après la limite d'acceptation de qualité (LAQ), 
          pour les contr&ocirc;les lot part lot 
          des caractéristiques de qualité indépendantes</full>
      </title-wrap>
      
      <doc-ident>
        <sdo>ISO</sdo>
        <proj-id>?????</proj-id>
        <language>en</language>
        <release-version>IS</release-version>
        <urn>urn:iso:std:iso:3951:-2:ed-1:v1:en</urn>
      </doc-ident>
      <std-ident>
        <originator>ISO</originator>
        <doc-type>is</doc-type>
        <doc-number>3951</doc-number>
        <part-number>2</part-number>
        <edition>1</edition>
        <version>1</version>
        <suppl-type></suppl-type>
        <suppl-number></suppl-number>
        <suppl-version></suppl-version>
      </std-ident>
      <content-language>en</content-language>
      <std-ref type="dated">ISO 3951-2:2006</std-ref>
      <std-ref type="undated">ISO 3951-2</std-ref>
      <doc-ref>ISO 3951-2:2006(E)</doc-ref>
      <pub-date>2006-03-31</pub-date>
      <release-date>2006-03-31</release-date>
      <comm-ref>ISO/TC 69/SC 5</comm-ref>
      <secretariat>BSI</secretariat>
      <ics>03.120.30</ics>
      <page-count count="46"/>
    </iso-meta>
    
    <sec sec-type="foreword">
      <title>Foreword</title>
      <p>ISO (the International Organization for
	Standardization) is a worldwide federation of
	national standards bodies ...</p>
      <p>International Standards are drafted in accordance
	with the rules given in the ISO/IEC Directives,
	Part 2.</p>
      <p>The main task of technical committees is to prepare
	International Standards. Draft International
	Standards adopted by the technical committees 
        ...</p>
      <p>Attention is drawn to the possibility that ... patent rights.</p>
      ...
    </sec>
    <sec sec-type="intro">
      <title>Introduction</title>
      <p>This part of ISO 3951 specifies an acceptance
	sampling system of single sampling plans for
	inspection by variables. It is indexed in terms of
	the Acceptance Quality Limit (AQL), and is of a
	technical nature, aimed at users who are already
	familiar with sampling by variables or who have
	complicated requirements. (An introductory treatment
	is given in ISO 3951‑1.)</p>
      <p>
        The objectives of the methods laid down in this part
	of ISO 3951 are to ensure that lots of an acceptable
	quality have a high probability of acceptance and
	that the probability of not accepting inferior lots
	is as high as practicable. This is achieved by means
	of the switching rules, which provide
        <list list-type="ordered">
          <list-item>
            <label>a)</label>
            <p>automatic protection to the consumer (by
	      means of a switch to tightened inspection or
	      discontinuation of sampling inspection) should
	      a deterioration in quality be detected;</p>
          </list-item>
          <list-item>
            <label>b)</label>
            <p>an incentive (at the discretion of the
	      responsible authority) to reduce inspection
	      costs (by means of a switch to a smaller
	      sample size) should consistently good quality
	      be achieved.</p>
          </list-item>
        </list>
      </p>
        
      <p>
	In this part of ISO 3951, the acceptability of a lot
	is implicitly or explicitly determined from an
	estimate of the percentage of nonconforming items in
	the process, based on a random sample of items from
	the lot.</p>
      <p>...</p>
      <p>Table 1 is intended to facilitate the use of this
	part of ISO 3951 by directing the user to the
	paragraphs and tables concerning any situation with
	which he may be confronted. Table 1 only deals with
	Clauses 15, 16, 17, 18, 19, 23, 24 and 25; in every
	case, it is necessary first of all to have read the
	other clauses.</p>
      ...
    </sec>  
  </front>
  <body>
    <sec sec-type="scope">
      <label>1</label>
      <title>Scope</title>
      <p>This part of ISO 3951 specifies an acceptance
	sampling system of single sampling plans for
	inspection by variables, indexed in terms of the
	Acceptance Quality Limit (AQL).</p>
      ...
    </sec>
    
    <sec sec-type="norm-refs">
      <label>2</label>
      <title>Normative references</title>
      <p>The following referenced documents are indispensable ...</p>
      <ref-list>
        <ref content-type="standard">
             <std>ISO 2859-1:1999, Sampling procedures for
	      inspection by attributes — Part 1: Sampling
	      schemes indexed by acceptance quality limit
	      (AQL) for lot-by-lot
	      inspection</std>
        </ref>
      </ref-list>
    </sec>
    
    <sec sec-type="terms">
      <label>3</label>
      <title>Terms and definitions</title>
      <p>For the purposes of this document, the terms and definitions
	given in ...</p>
     <sec>
       <label>3.1</label>
       <title>inspection by variables</title>
       <p>inspection by measuring the magnitude(s) of a
	  characteristic(s) of an item</p>
       <p><ext-link ext-link-type="iso-std">[ISO 3534-2]</ext-link></p>
     </sec>
      ...     
      <sec>
        <label>3.8</label>
        <title>consumer’s risk quality</title>
        <p>CRQ</p>
        <p>quality level (3.7) of a process which, in the
	  acceptance sampling plan, corresponds to a
	  specified consumer’s risk</p>
        <list list-type="simple">
          <list-item>
            <label>NOTE 1</label>
            <p>In this part of ISO 3951, the quality level
	      is the process fraction nonconforming.</p>
          </list-item>
          <list-item>
            <label>NOTE 2</label>
            <p>In this part of ISO 3951, the consumer’s risk
	      quality is such that the consumer’s risk is 10%.</p>
          </list-item>       
        </list>
</sec>
      ...       
    </sec>
    
    <sec sec-type="symbols">
      <label>4</label>
      <title>Symbols</title>
      
      <sec>
        <label>4.1</label>
        <title>Univariate symbols</title>
        <p>The symbols used when there is only one quality
	  characteristic in the class are as follows.</p>
       <def-list>
         <def-item>
           <term><italic>f<sub>s</sub></italic></term>
           <def>
             <p>factor that relates the maximum sample
		standard deviation (MSSD) to the difference
		between <italic>U</italic> and
		<italic>L</italic> (<xref>see Annex
		  D</xref>)</p>
           </def>
         </def-item>
         ...  
       </def-list>
      </sec>
      
      <sec>
        <label>4.2</label>
        <title>Multivariate symbols</title>
        <p>Further symbols used when there are two or more
	  quality... </p>  
          ...  
      </sec>
    </sec>
    <sec>
      <label>5</label>
      <title>Acceptance quality limit (AQL)</title>
      <sec>
        <label>5.1</label>
        <title>Concept</title>
        <p>The AQL is the quality level that is the worst
	  tolerable process fraction nonconforming when a
	  continuing series of lots is submitted for
	  acceptance sampling. ...
	</p>
        ...
      </sec>
      
      <sec>
        <label>5.2</label>
        <title>Use</title>
        <p>The AQL, together with  ...</p>
        ...        
      </sec>
      ...
    </sec>
    ...    
  </body>
  <back>
 <app-group>
   <app content-type="norm-annex">
     <label>Annex A</label>
     <annex-type>(normative)</annex-type>
     <title>Tables for determining the appropriate sample size</title>
     <table-wrap>
       <label>Table A.1</label>
       <caption><p>Sample size code letters and inspection levels</p></caption>
       <table>
         <thead>
         <tr>
           <th>Lot or batch size</th>
           <th>Special inspection levels</th>...
         </tr>
         <tr><th>S-1</th><th>S-2</th>...</tr>
       </thead>
         <tbody>
           ...
         </tbody>
       </table>
       <table-wrap-foot>
         <fn><label>NOTE</label>
           <p>The sample size code letters and inspection
		levels in this part of ISO 3951 correspond
		to those given in ISO 2859 1 and ISO
		3951-1.</p>
         </fn>
         
       </table-wrap-foot>
     </table-wrap>
   </app>
 </app-group> 
  </back>
</standard>