Sampling Scheme

[Former Member]

Hello dear experts,

I've done some researches on the following elements of the sampling scheme :

- Attributive inspection

- Variable inspection

- Inspection without a valuation parameters

- Inspection severity

- AQL

And that's what i understood please confirm if it's right.

1- Attributive inspection uses the acceptance level and rejection level to decide whether the sample is accepted or rejected (after comparing it with the number of nonconforming units for this sample.

2- Variable inspection is used for quantitative characteristics and on the basis of ceartain parameters (mean value, standard deviation, USL, LSL and K factor) related to the sample, we are able to decide wether this sample is accepted or rejected.

3- Inspection without a valuation parameters is used to only have information about lot size and sample size without setting any acceptance criteria.

4- Inspection severity can modify automatically the sample size according to the value it takes (for the case of tightened and reduced inspection).

5- AQL is related to the acceptance or rejection of the lot.if the percentage of the rejected samples exceeds de value of the AQL the lot is rejected.

Please correct if wrong.

Thank you.

[former_member42743 · Accepted solution]

Just wanted to clarify your first two.  The other three are pretty much on target.

Attributive is bascially based on numbers.  It can be based on:

     - Simply the selected set choice, regardless of the sample size,

     - the number of defects, (i.e ten total defects seen, regardless of number of failed units)

     - the number failed units, (i.e. failed units regardless of number of defects)

Variable is related to charting, like SPC.  It's not necessarily used for all quantitative characteristics and you need the SPC indicator flag on in the MIC I beleive.

Quantitiative characteristics usually use "700 - Mean value within tolerance range"

Craig

[Former Member · Accepted solution]

Thank u so much Craig