DPSCM 4155.18
DPSC STQP
l JUN 84
FOREWORD
(Supplementation is prohibited.)
DPSC Manual 4155.18 is published by the Defense
Personnel Support Center for use by Government personnel assigned
to inspection of items procured on DPSC subsistence contracts.
Instructions are applicable to contractor personnel.
This Manual will be maintained in a current status and
reviewed annually.
Users of this publication are encouraged to submit
recommended changes and comments to improve the publication,
through channels, to Directorate of Subsistence, ATTN:
DPSC-STQP.
BY ORDER OF THE COMMANDER
PATRICIA FENWICK
Ch, Administrative Services Div
Directorate of Installation Srv
DISTRIBUTION
Special
ST-B thru ST-Q
DLA-IG and DLA-IGROs - 1 each
DPSC-IAA/Library - 2
DPSC-IO - 25
___________
This Manual supersedes DPSC Manual 4155.18, 1 Jul 78, and Change
No. 1.
*Denotes Changes.
DPSCM 4155.18
I. REFERENCES.
A. $(SK) MILSTD105, Sampling Procedures and Tables for
Inspection by Attributes.
B. MILSTD109, Quality Assurance Terms and Definitions.
C. MILHDBK53, Guide for Sampling Inspection.
D. DPSC Manual 4155.5, Subsistence Contractor Inspection
Procedures Manual.
E. DPSC Manual 4155.6, Subsistence Inspection Manual.
II. PURPOSE AND SCOPE. The purpose of this Manual is to provide
information regarding statistical sampling plans. This Manual is
applicable to Government personnel performing inspection on DPSC
subsistence contracts and may be used in briefing contractor's
personnel on contractor inspection procedures.
III. DEFINITIONS.
A. Major Total Defects Concept. This calls for assignment of
separate Acceptable Quality Levels (AQLs) for each major class of
defects and an AQL for the combined major and minor classes of
defects. An AQL is not assigned to the minor class of defects,
but the sampling plan for total defects pertains to the total of
major defects plus minor defects found in the sample.
To standardize procedures and minimize confusion in using
MILSTD105 to obtain a sampling plan (i.e. sample size, acceptance
and rejection numbers) when a Table of Examination has more than
one class of defects (e.g. major, minor, total) and a combination
of AQLs, the inspector should follow the instructions in the
applicable table of MILSTD105 to arrive at one sample size, with
corresponding acceptance and rejection numbers, to be used for all
classes of defects in the examination. When there are compelling
reasons to use separate sample sizes for the different classes of
defects, approval will be obtained from the quality assurance
element of the contracting activity.
B. Major-Minor Defects Concept. Such plans require separate
AQLs for each class of defects, i.e., major and minor. This makes
it possible for the sample size to vary for each class of defects.
However, to minimize confusion and to facilitate application, it
is preferable that the sample size be the same for all classes of
defects in an examination, as for the major-total defects concept.
This concept is currently being stressed in Military and Federal
specifications more than the major total defects concept.
DPSCM 4155.18
IV. SAMPLING PLAN EXPRESSION OF NONCONFORMANCE.
A. All sampling plans used by DPSC refer to MILSTD105 unless
otherwise specified in the contract documents. They contain
criteria for determining product acceptability or nonconformance
as follows:
1. "Defects per Hundred Units" (DHU or DPHU) expresses
nonconformance based on the number of defects in the sample.
2. "Percent Defective" (PD) expresses nonconformance based on
the number of units in the sample that contain one or more
defects.
B. The elements of inspection, i.e., examination and testing,
may use either term of expression of nonconformance in the
sampling plans applied.
V. TYPES OF SAMPLING PLANS.
A. MILSTD105 is based on inspection by attributes, i.e., based
on a characteristic either meeting or not meeting a requirement.
Single, Double, Multiple, Reduced, Normal and Tightened Sampling
Plans are provided. Tables XA thru XR of MILSTD105 depict
approximate operating characteristic curves for the single
sampling plans. Matching of the single sampling plan used to the
corresponding operating characteristic curve provides an
understanding of the producer and consumer risks associated with
the particular single sampling plan. Producer risks are those
associated with the rejection of lots of good quality, whereas
consumer risks are those associated with the acceptance of lots of
poor quality.
1. "Single" sampling is ordinarily used because it provides
the most information at least cost when quality is at or near the
Acceptable Quality Level.
2. Double or multiple sampling may be feasible when history
records or observation of production at a plant show that quality
is markedly worse or markedly better than the AQL.
3. The type of sampling plan is omitted from Quality Assurance
Provisions of contractual documents to permit flexibility in field
inspection quality assurance operations.
DPSCM 4155.18
B. Attribute sampling plans are identified as to severity of
inspection, i.e., normal, tightened or reduced. The degree of
inspection and the procedures for switching from one degree to
another are explained in paragraph 8 of MILSTD105. In accordance
with these procedures, MILSTD105, Tables I, IIA, IIIA, and IVA are
used for normal inspection. Tables I, IIB, IIIB, and IVB are used
for tightened inspection. Tables I, IIC, IIIC, and IVC are used
for reduced inspection. This manual illustrates the extraction of
sampling plans using normal inspection. The extraction of
tightened or reduced sampling plans is performed in the same
manner using the appropriate "B" or "C" series tables.
C. Under the major total defects concept, the entire examination
(all classes) will be subjected to tightened inspection when any
one class in the examination qualifies for such inspection. Under
the major minor defects concept only the affected class need be
subjected to tightened inspection. Reduced inspection is
discouraged due to the high risks associated with the reduced
sampling plans.
D. Lot Average and Composite Sampling Plans, based on a
continuous scale of measurement of lot characteristic
requirements, are also used by DPSC.
1. Examples are net weight, net volume and milk fat content.
2. These sampling plans may be effected in two ways:
a. Lot Average Inspect each sample unit, record the
individual results and compute the average. Compare this value
with the average specification requirement to determine lot
conformance.
b. Composite Form a composite sample by intermingling and
blending the individual units. (Equal portions from each unit may
be used.) Inspect the composite sample and compare the results
with the specification requirement.
3. The contractual documents will indicate whether the lot
average or composite sampling plan is to be used.
DPSCM 4155.18
VI. APPLICATION OF SAMPLING PLANS.
A. General.
1. The contract, or documents referenced in it, will specify
the Inspection Levels and AQLs designating the sampling plans
applicable to each element of inspection to be performed. For
example, the contract may call for examination of primary
containers, of net weight, and of product organoleptic qualities,
and testing of physical and chemical properties of the product and
component items.
2. The factors for determining the sample sizes to be used for
each examination or test are:
a. The concept indicated, i.e., whether major total defects
concept or major minor defects concept.
b. The Inspection Level.
c. The AQL.
d. The type of sampling plan utilized, i.e., single, double,
or multiple.
e. The severity of inspection required, i.e., normal,
tightened or reduced.
B. Example of Uses of Single Sampling Plans for Major Total
DefectsConcept under Normal Inspection.
This example involves single sampling of a lot of 3,250
primary containers.
The specified inspection is Level II and AQLs are 0.15 DHU for
Major A defects,
1.0 DHU for Major B defects, and 4.0 DHU for Total defects.
a. Referring to MILSTD105, Table I, with the lot size of
3,250 containers and Inspection Level II, we derive sample size
code letter "L".
b. Referring code letter "L" to Table IIA of MILSTD105, we
find that the corresponding sample size is 200 units (primary
containers). Following this row horizontally to the right to
determine the acceptance and rejection numbers associated with
this sample size for the AQLs stipulated, we find an arrow
pointing downward in the 0.15 AQL column, 5 and 6 respectively in
the 1.0 AQL column, and 14 and 15 respectively in the 4.0 AQL
column. Since these sampling plans use the major total defects
concept, it is preferred that the sample size be increased to 315
for all of the AQLs stipulated and not for just the Major A
defects plan with an AQL of 0.15. Therefore, the proper sampling
plans are:
DPSCM 4155.18
Sample Size Major A
Major B Total
AC RE AC
RE AC RE
3l5 l 2 7
8 21 22
c. Under the major total defects concept, the number of
minor defects permitted is reduced by the number of major defects
found. Therefore, if one defect of Major A class is found, only
20 minor defects will be tolerated, provided no defects of Major B
class are found without the lot being considered nonconforming.
Similarly, the finding of any defects of Major B class reduces,
still further, the number of minor defects permitted.
C. Example of Use of Multiple Sampling Plans for Major Total
Defects Concept under Normal Inspection.
This example involves sampling of a lot of 1,250 primary
containers. The specified Inspection Level is II and AQLs are
0.065 DHU for Major A defects, 1.0 DHU for Major B defects and 4.0
for Total defects. (Sampling examinations of prior lots indicated
that the quality was consistently better than the specified AQL
and administrative decision permitted use of multiple sampling.)
a. Referring to MILSTD105, Table I, with lot size of 1,250
units (containers) and Inspection Level II, we derive sample size
code letter "K".
b. Referring code letter "K" to Table IVA of MILSTD105, we
find a cumulative sample size of 224 units for seven increment
sample sizes of 32 units each. Following these rows horizontally
to the right, instead of criteria we find an arrow directing us
downward in the 0.065 AQL column. Note, however, that the block
below the arrow also lacks criteria for this next code letter "L".
The asterisk in the block for code letter "L" and AQL of 0.065
indicates use of the corresponding single sampling plan rather
than the multiple sampling plan.
DPSCM 4155.18
c. Referring code letter "L" to Table IIA, we find the
proper sampling plans are:
Sample Size Major A
Major B Total
AC RE
AC RE AC RE
200 0 1
5 6 14 15
d. When different sample sizes are indicated for the same
examination or test in a lot, the entire amount of samples drawn
for that inspection element ordinarily should not exceed the
larger of the sample sizes. To facilitate the physical job of
sampling, the larger sample should be drawn. As it is drawn, the
lesser sample should be differentiated by marking and, if
convenient, by physical separation from the units that bring the
sample amount up to the size of the larger quantity.
Differentiation should take place at the time the sample units are
drawn, i.e., before any examination or testing is performed, to
preclude bias in sampling. If examination or testing preceded
differentiation, bias may be introduced intentionally or
inadvertently by redistributing defective units from the sequence
of drawing. Such redistribution of defective units could result
in a decision about conformance of the lot differing from what
would properly have been indicated. When multiple sampling is to
be used, consideration should be given to such factors as repeated
availability of forklift equipment, repeated tearing down and
rebuilding stacks of boxes, etc., as successive increment sample
sizes may be required. Should these factors appear prohibitive as
to time and effort, the entire cumulative sample size should be
drawn from sufficient shipping containers in accordance with
instruction as to number of units to be extracted per shipping
container or case (e.g., not more than two units). The cases
could then be opened as the need arose for successive increment
sample sizes. Expansion of this general topic and examples
follow.
DPSCM 4155.18
e. In double or multiple sampling, differentiation of the
increment sample size will be necessary for inspection in the
proper sequence, if the indicated entire cumulative sample size is
drawn; for example, the multiple sampling plans in Table IVA for
code letter "G" and AQLs of 2.5 DHU for major defects and 10.0 DHU
for total defects are:
Cumulative
Sample Sample
Major Total
Sample
Size Size
AQL 2.5 AQL 10.0
AC RE AC RE
First
8 8
# 2 0 4
Second
8 16
0 3 1 6
Third
8 24
0 3 3 8
Fourth
8 32
1 4 5 10
Fifth 8 40
2 4 7 11
Sixth
8 48
3 5 10 12
Seventh
8 56
4 5 13 14
It should be noted that upon examination of the first sample size
of eight units, a decision of nonconformance can be reached if two
or more major defects, or four or more major and minor defects
combined, or if both events occur. However, a decision of
conformance cannot be reached before the second increment sample
size has been inspected under this plan as the "#" means
acceptance is not permitted at this sample size.
DPSCM 4155.18
D. Single Sampling Plans: Major-Minor Defects Concept.
1. Under the major-minor defects concept, more than one sample
size per examination or testing may occur in both single sampling
and double or multiple sampling. It is preferable to arrive at
one sample size for all classes of defects in the examination (see
paragraph VI.B.). Should compelling reasons exist for using a
different sample size for each class of defects in the
examination, the following means will be used to differentiate the
various sample sizes.
2. Single sampling for major minor concept entails drawing the
large sample indicated by MILSTD105 and separating the smaller
sample size either by marking or physical separation, or both, at
the time the sample units are drawn. For example, Inspection
Level S2 and AQLs of 1.5 DHU for major defects and 4.0 DHU for
minor defects applied against a lot of 6,500 units indicates
sample size code letter "D" in Table I. Referring to Table IIA
with code letter "D", we find acceptance criteria associated with
the corresponding sample size 8 for the AQL of 1.5 DHU and an
arrow directing us downward to a larger sample size for the AQL of
4.0 DHU. Therefore, the proper sampling plans are:
Class of Sample Acceptance Rejection
Defects Size No. No.
Major 8 0 1
Minor 13 1 2
Therefore, a maximum sample of 13 units should be drawn from the
lot. The first randomly drawn units comprising the lesser sample
size are differentiated by marking or tagging from the rest of the
units that bring the total number up to the larger sample size.
In this example, the lesser sample size (the first eight units
drawn) shall be examined and the units scored for all classes of
defects, i.e., majors and minors. The remaining units that
complete the larger sample size (five in this example) shall be
examined and the units scored for the applicable class of defects
(minor defects in this example) only.
DPSCM 4155.18
E. Multiple Sampling Plans: Major-Minor Defects Concept.
1. This circumstance requires more attention to the sequence
in which the sample units are inspected for each class in order to
comply with the randomness of selection. For example, Inspection
Level I and AQLs of 1.0 DHU for major defects and 6.5 DHU for
minor defects applied against a lot of 790 units indicates sample
size code letter "G" in Table I. Referring to Table IVA with code
letter "G", we find an arrow directing us downward to a larger
sample size for the AQL of 1.0 DHU than for the sample sizes
corresponding to code letter "G" for the AQL of 6.5 DHU.
Therefore, the proper sampling plans are:
MAJOR DEFECTS MINOR DEFECTS
Cumulative Cumulative
Sample Sample Sample Sample
Sample Size Size AQL 1.0 Size Size
AQL 6.5
AC RE
AC RE
First 13 13 # 2 8
8
# 4
Second 13 26 # 2 8 16
1 5
Third 13 39 0 2 8 24
2 6
Fourth 13 52 0 3 8 32
3 7
Fifth 13 65 1 3 8 40
5 8
Sixth 13 78 1 3 8 48
7 9
Seventh 13 91 2 3 8 56
9 10
2. To best illustrate the need for differentiation of the
sample sizes for each class of defects and the sequence of
inspection, the larger entire cumulative sample size will be drawn
as indicated.
DPSCM 4155.18
Entire Cumulative Sample Size for Major Defects
1st 2nd 3rd 4th 5th 6th 7th
18 913 1416 1724 2526 2732 3339 40 4148 4952 5356 5765 6678 7991
1st 2nd 3rd 4th 5th 6th 7th
Entire Cumulative Sample Size for Minor Defects
3. Inspection should proceed as follows:
a. Examine units 1 through 8 for minor defects. If four or
more minor defects are found, the lot is nonconforming and no
further examination need be made for minor defects. If 0, 1, 2,
or 3 minor defects are found, units 9 through 16 must be examined
from the cumulative sample for minor defects.
b. Examine units 1 through 13 for major defects. If two or
more major defects are found, the lot is nonconforming and no
further examination need be made for major defects. If 0 or 1
major defect is found, units 14 through 26 must be examined from
the cumulative sample size for major defects.
c. If examination of units 1 through 16 revealed 0 or 1
minor defect, the lot is conforming for minor defects and no
further examination for that class of defects need be made.
Similarly, if not more than three minor defects were found in the
first eight units and the cumulative sample of 16 units revealed
five or more minor defects, the lot is nonconforming and no
further examination for that class of defects need be made. If 2,
3, or 4 minor defects were found in the cumulative sample of 16
units, examination of units 17 through 24 must be made for minor
defects.
d. If examination of units 1 through 26 revealed two or more
major defects, the lot is nonconforming for major defects and no
further examination for that class of defects need be made. If 0
or 1 major defect is found in the 26 units examined thus far,
units 27 through 39 must be examined for major defects. It should
be noted that while a decision that the lot conforms for the minor
defect class requires examining 16 units as a minimum; to reach
the same decision for the major defects class requires examining
39 units as a minimum.
DPSCM 4155.18
4. The procedure for inspecting successive increment sample
sizes is continued for any class until the number of defects for
that class indicates nonconformance by equaling or exceeding the
rejection number, or indicates conformance by being less than or
equal to the acceptance number. Note that if 0 or 1 minor defect
had been found in units 1 through 16, examination for major
defects would continue through 39 units, at least, if less than 2
major defects were found. Any minor defects found starting with
unit 17 would not be scored or recorded since the lot had been
found conforming to the criteria for the cumulative sample size
for the second increment for minor defects. Similarly, if 0 major
defects had been found in units 1 through 39 and examination for
minor defects had to continue through unit 40, any major defects
found starting with unit 40 would not be scored or recorded. The
lot had been found conforming to the criteria for the cumulative
sample size for the third increment for major defects. Scoring or
recording defects of any particular class found after reaching a
valid decision of conformance for that particular class on a
previous sample size violates the doctrine of statistical
sampling.
5. Generally speaking, for each examination or test the
entire single sample or first increment sample size of double or
multiple sampling must be examined or tested. This is necessary
in order to obtain a sufficiently accurate picture as to quality
of the lot. Under certain conditions, however, it may not be
desirable after the rejection number has been reached to complete
inspection of the entire sample. When either of the conditions
below apply, the inspection record will be annotated "Inspection
stopped after...units because....". The blanks will be filled in,
respectively, with the number of units and the reason for
stopping, e.g., "moving lot inspection" or "improper nomenclature
printed on cases." Conditions for halting inspection upon
reaching the rejection number are:
a. When moving lot inspection is specified, the inspector
will discontinue examination once the rejection number has been
reached.
DPSCM 4155.18
b. When the defect is an overall or general defect, e.g.,
wrong markings printed on the shipping cases, wrong colored ink
used for markings, cans not coated when coating is required, or
vice versa, etc., that will appear in each unit in the lot, the
inspector will discontinue each examination once the rejection
number has been reached.
F. Example of Double Sampling Plans: Major-Minor Defects
Concept. This example involves sampling of a lot of 2,000 items.
The specified Inspection Level is I and the AQLs are 1.0 DHU for
major defects and 6.5 DHU for minor defects. A normal sampling
plan is authorized.
a. Referring to MILSTD105, Table I, with lot size of 2,000
items and Inspection Level I, sample size code letter "H" is
derived.
b. From Table IIIA, sample size code letter "H" and AQLs of
1.0 and 6.5, the following sampling plans are obtained.
Cumulative AQL AQL
SampleSize Sample Size 1.0 6.5
AC RE AC RE
First 32 32
0 2 3 7
Second 32 64
1 2 8 9
c. From the first sample of 32 units, the lot is accepted if
no major defects and if 3 or fewer minor defects are found. The
lot is rejected if 2 or more major defects and/or if 7 or more
minor defects are found. However, no decision can be made from
the results of the first sample if 1 major defect and/or 4, 5 or 6
minor defects are found. A second sample of 32 items must be
taken. If the combined sample size of 64 items contains 1 or
fewer major defects and 8 or fewer minor defects, the lot is
accepted. If the combined sample size of 64 items contains 2 or
more major defects and/or 9 or more minor defects the lot is
nonconforming.
DPSCM 4155.18
d. The decision whether to draw the first sample, perform
examination, and then draw the second sample if required, or
whether to draw two samples before examination would depend on the
particular circumstances involved (see paragraph VI.C.d.).
G. Lot Average or Composite Sampling Plans. Lot average or
composite sampling plans make use of MILSTD105 only for
determining the sample size. These sampling plans call for other
considerations before a decision is made on the lot acceptability
when an apparent nonconformance is indicated by the results of the
samples. Detailed information on lot average sampling plans is
contained in DPSC Manual 4155.6. An example of determining the
sample size from MILSTD105 for a lot average sampling plan would
be where the instructions read: "The sample size shall be the
number of primary containers indicated by Inspection Level S1.
Test requirements shall be lot average requirements." If the lot
consisted of 24,000 primary containers of product, reference to
Table I, MILSTD105, indicates code letter "C". Referring to Table
IIA with code letter "C", we find the sample size to be 5 units.
The MILSTD105 acceptance criteria, i.e., AQLs and Acceptance and
Rejection Numbers, are not employed for lot average
determinations.
H. Lot Acceptance-Rejection Criteria. A lot shall be considered
acceptable or conforming to requirements only if it passes every
sampling plan applied. If the lot fails one or more sampling
plans, it shall be considered unacceptable or nonconforming to
requirements.
VII. INSTRUCTIONS FOR THE USE OF LIMITING QUALITY (LQ) VALUES.
A. General.
1. These values are applicable in those instances when it is
desirable to control quality at particular consumer's risk (Pa)
for isolated lots. When using MILSTD105 this is accomplished by
the selection of a sampling plan that provides not less than a
specified LQ protection and is associated with a designated AQL
value. When the contractual documents stipulate an LQ value for
a table of defects, the sampling plan shall be selected in
accordance with the instructions of Section 11 of MILSTD105.
This sampling plan shall be compared to the plan indicated by the
Inspection Level and AQL without application of LQ information.
The plan requiring the larger sample size will be used.
DPSCM 4155.18
2. When LQs with the associated consumer's risk expressed as
percent are used, they will be placed in contractual documents and
will be identified as to Inspection Level and AQL to which they
apply in any examination. An LQ value may be specified for one or
more AQLs and for any examination or test.
B. Sampling Plan - Limiting Quality Protection.
This example involves examination of a single lot
(20,000 units) of ration component produced on contract. The
following inspection data applies:
AQLsLQs
Insp. Sample Lot Size
Level Unit Expressed as Major A Major B
Total
S2
Contents of Primary 0.65 2.5
10.00
Primary Container Container LQ = 8 DHU
Pa = 10%
a. Refer to Table I, MILSTD105. For lot size of 20,000 with
Inspection Level of S2, the sample size code letter indicated is
"D".
b. Refer to Table IIA, MILSTD105, for code letter "D". In
AQL column, headed 0.65, an arrow points downward resulting in the
following sampling plan:
DEFECTS
Sample Size Major A Major B Total
AC RE AC RE AC RE
20
0 1 1 2 5 6
c. Refer to Table VIB, MILSTD105. Contract specifies an LQ
of 8 DHU. In AQL column, headed 0.65, locate the value, equal to
or less than 8, which is "4.9". The sample size indicated is "80"
and the code letter is "J".
DPSCM 4155.18
d. Refer to Table IIA, MILSTD105, for sampling plan for
sample size code letter "J". Since the LQ sample size of 80 is
greater than the sample size 20 indicated for code letter "D"
(paragraph VII.B.b.), the following plan will apply:
DEFECTS
Sample Size Major A Major B Total
AC RE AC RE AC RE
80
1 2 5 6 14 15
e. In the above example, if the stipulated Inspection Level
were "II" instead of "S2", Table I, MILSTD105, would have
indicated the sample size code letter to be "M". Refer to Table
IIA, MILSTD105, for code letter "M". An upward pointing arrow is
encountered in the AQL column headed 10.0, which results in the
following sampling plan:
DEFECTS
Sample Size Major A Major B Total
AC RE AC RE AC RE
125
2 3 7 8 21 22
f. The plan indicated by the LQ value would be the same as
in paragraph VII.B.d. Since the sampling plan resulting from
application of the LQ value has a smaller sample size and offers
less protection than the sampling plan resulting from application
of the Inspection Level and the AQL, the latter plan with the
larger sample size is applied.
VIII. INSTRUCTIONS FOR COUNTING DEFECTIVES.
A. This Manual has thus far discussed defects and methods of
scoring defects. Some Quality Assurance Provisions are concerned
with defective units rather than defects. Basically, a
"defective" is a unit which contains one or more defects. A major
defective is a unit containing one or more major defects; a minor
defective is a unit containing one or more minor defects.
Depending upon classification of defects, a unit may be scored
simultaneously as a major defective and a minor defective, or
simply as a defective.
DPSCM 4155.18
B. There are two procedures for classifying defects:
1. Procedure A: The Quality Assurance Provisions make no
separation between majors and minors all defects are treated as a
single class.
2. Procedure B: The Quality Assurance Provisions separate
major and minor defects they are counted separately.
C. Counting: Procedure A. When all defects are treated as a
single class, the first defect found is tallied as "1". Any
subsequent defects in that same unit are tallied as "0". For
example, in a shipping container the inspector finds three
different defects. He records:
1. Staples too far apart 1.
2. Not properly glued 0.
3. Ply separation 0.
D. Upon completion of inspection of his sample size, he
determines the quality of the lot by counting the tallied "1s".
For example, if the sample contains 13 units, the following might
illustrate results of examination of shipping containers.
Defects
12 3 4 5 6 7 8 9 10 11 12 13
Ply Separation 1 1 1 1 1
1 1 1
Not properly glued 0 0 1 0
0 0
Staples too far apart 0 1 0 0
1
Marking illegible 0 0 0
0 0
Units numbered 6 and 12 contained no defects.
The total number of defects found is 24.
The total number of defectives found is 11.
NOTE: ( ) indicates no defect found for
that characteristic.
DPSCM 4155.18
E. Counting: Procedure B.
1. Major and minor defects are scored and counted separately
when classified separately. The first major defect found on a
unit is tallied "1"; the first minor defect found on a unit is
tallied "1". If a major and a minor defect are found on the same
unit, a "1" is tallied for major and a "1" is tallied for minor.
Subsequent defects for either class of defects after the first
defect is tallied as "0". Upon completion of inspection of his
sample size, he determines the quality of the lot by counting the
tallied "1s". For example:
Major Minor
Defect 103 10111
Defect 211 10
Defect 106 01
Defect 214 001
Defect 221 1
2. The total number of major defects is 7; the total number of
major defectives is 5.
3. The total number of minor defects is 6; the total number of
minor defectives is 3.