BS 6002-4.1:1994

Committees responsible
National foreword
Specification
Section 1. General
1.1 Scope
1.2 Normative references
1.3 Definitions and symbols
1.4 Principle of sequential sampling by variables
Section 2. Choice of sampling plan
2.1 Factors determining the choice of a sequential
     sampling plan by variables
2.2 Particular reservations on the inspection of small
     lots
2.3 Selection of a sampling plan
2.4 Pre-operation preparations
Section 3. Operation of a sequential sampling plan
3.1 Specification of the plan
3.2 Preparing the sampling plan
3.3 Drawing of the sample
3.4 The cumulative leeway
3.5 Determination of acceptability
3.6 Operating characteristic curves and average sample
     size
Annexes
A (normative) Sequential sampling plans corresponding
     to ISO 3951 single sampling plans
B (normative) Determination of the parameters of a
     sequential sampling plan
C (normative) Calculation of operating characteristic
     curve and average sample size
D (informative) Bibliography
Tables
1 Sequential sampling plans by variables for percent
     nonconforming for producer's risk alpha = 0,05 and
     consumer's risk beta = 0,10
2 Values of psi for limiting process standard
     deviation LPSD (combined double specification
     limits)
3 Values of f for maximum process standard deviation
     MPSD (separate double specification limits)
A.1 Sequential sampling plans corresponding to ISO
     3951 single sampling plans for normal, tightened
     and reduced inspection (master table)
A.2 Curtailment values for the sequential sampling
     plans of table A.1
A.3 Values of psi for limiting process standard
     deviation, LPSD (combined double specification
     limits), for the sequential sampling plans of table
     A.1
A.4 Values of f for maximum process standard deviation,
     MPSD (separate double specification limits), for
     the sequential sampling plans of table A.1
A.5 Average sample size for the sequential sampling
     plans of table A.1
Figures
1 Operating characteristic curve for a sampling plan
     with producer's risk alpha = 0,05 and consumer's
     risk beta = 0,10
2 Inspection record sheet for the sequential sampling
     plan for a single specification limit considered in
     the example given in 3.2.1.3
3 Acceptance chart for the sequential sampling plan
     for a single specification limit considered in the
     example given in 3.2.1.3
4 Inspection record sheet for the sequential sampling
     plan for combined double specification limits
     considered in the example given in 3.2.2.3
5 Acceptance chart for the sequential sampling plan
     for combined double specification limits considered
     in the example given in 3.2.2.3
6 Inspection record sheet for the sequential sampling
     plan for separate double specification limits
     considered in the example given in 3.2.3.3
7 Acceptance chart for the sequential sampling plan
     for separate double specification limits considered
     in the example given in 3.2.3.3
8 Acceptance chart for the sequential sampling plan
     for a single specification limit considered in the
     example given in 3.5.1.3
9 Acceptance chart for the sequential sampling plan
     for combined double specification limits considered
     in the example given in 3.5.2.3
10 Acceptance chart for the sequential sampling plan
     for separate double specification limits considered
     in the example given in 3.5.3.3
C.1 Operating characteristic curve for the sequential
     sampling plan considered in the example given in
     C.2.3
C.2 Curve showing the average sample size for the
     sequential sampling plan considered in the example
     given in C.3.3

Complements BS 6001-4. Provides a wide range of plans, including plans that supplement and match the corresponding plans in BS 6002-1. Applies only to single, at least approximately normally distributed quality variables. Only for use in continuing series of lots from the same production run.