K- Factor in sampling scheme

[former_member220469]

Dear All,

                         Can you please explain me what is K- FACTOR in Sampling scheme? what is the difference between AQL and K factor ? why should we enter K- Factor in sampling scheme?

As per my understanding, AQL value is the number of defects for an given inspection severity for which an inspection lot will be rejected

Example:

Inspection lot qty : 15

sample size :         10

AQL value            :  5

Inspection serverity:4- Nomal Inspection

Now if i reject 5 samples in the inspection lot for the sample size of 10, the whole inspection lot will get rejected.

Now where does the K-factor play a role in the sample size calculation for valuation parameter- Valuation by S-Method

Before posting the thread, i have searched enough threads which have given the  definition from "SAP HELP" .

Kindly solve the query

J.Balakrishnan

[former_member207800]

It is not easy to understand it.

I'd like to explain it briefly.

k (acceptability constant) = ( U - Xbar ) / S > k or ( L - Xbar ) / S > k

* U: upper spec. limit

* L: lower spec. limit

* S : standard deviation

AQL (acceptable quality level) decides which sampling table will be used.

Usually if the AQL value is increased, the sample size is reduced but more detailed sampling plan.

I don't recommend understanding it because most company don't use it currently.

If a company use it, they must be using certain sampling table based on ISO sampling plan. (SAP provides ISO sampling plan as default)

Regards, DoWook KIM

[former_member220469]

Sir,

                    Thank you very much

[Martin_H]

well, did you search SCN as well? like http://scn.sap.com/thread/605635?

Regards

MH

[former_member220469]

Sir,

                    Yes, i learnt this thread previously, but i am unable to understand the concept of K-factor given in this thread.

I have tried the sampling scheme by varialble inspection - by S- Method by two scenorios

Valuation parameter-  Variable inspection by S-method

Scenario : 1. Inspection severity + AQL value

   Inspection severity - 004- Normal inspection

   Lot size - 30

   Sample size - 15

   AQL value  - 5

   K-Factor    - 3

I have created an inspection lot with lot quantity 30 ea. Sample size is 15 Ea. While result recording, i reject 3 samples and i am valuation results, the whole inspection lot is getting rejected.

           As per my understanding of AQL values, if i reject the 5 samples in result recording, then the whole inspection lot has to be rejected.  In the above mentioned scenario, why whole inspection lot is getting  rejected when i reject only 3 samples ?

Scenario: 2 : Inspection severity

Inspection severity - 004- Normal inspection

Lot size                   - 15

sample size            - 5

K-Factor                  - 3

In this scenario, the whole inspection lot should get rejected, if 3 samples are rejected. But the whole inspection lot is getting rejected, even if i reject 1 sample ?

I have given the following parameters in sampling procedure

1. Sampling type -  Use sampling scheme

2. Valuation mode - variable inspection s- method (One limit)

3. Inspection point- No Inspection points

4. Multiple schemes - No multiple schemes

Kindly solve the query

J.Balakrishnan

[Martin_H]

Hi,

I propose you get familiar with the ISO standard 3951 (sampling procedures for inspections by variables). The respective concepts are explained in this standard.

Regards

MH