Acceptance Sampling by Variables - Compare

User-Defined Plans - Average Total Inspection (ATI)

  

The average total inspection per lot represents the relationship between the quality of the incoming material and the number of items that need to be inspected, assuming that rejected lots will be 100% inspected and defective items will be reworked and inspected again (rectifying inspection).

Example Output

Compare User Defined Plan(s)

 

 

 Sample     Critical   Defectives  Probability  Probability

Size(n)  Distance(k)  Per Million    Accepting    Rejecting    AOQ     ATI

    100      3.44914          100        0.854        0.146   83.0   612.3

    100      3.44914          600        0.224        0.776  130.8  2815.1

 

    150      3.44914          100        0.899        0.101   86.1   500.1

    150      3.44914          600        0.172        0.828   98.8  3007.3

 

    200      3.44914          100        0.928        0.072   87.6   444.7

    200      3.44914          600        0.135        0.865   76.3  3142.0

 

 

Sample     Critical     Maximum         At Defectives

  Size  Distance(k)  StDev(MSD)   AOQL    Per Million

   100      3.44914   0.0027533  145.6          369.7

   150      3.44914   0.0027533  138.5          288.9

   200      3.44914   0.0027533  136.7          256.4

 

Z.LSL = (mean - lower spec)/standard deviation

Z.USL = (upper spec - mean)/standard deviation

Accept lot if standard deviation ≤ MSD, Z.LSL ≥ k and Z.USL ≥ k; otherwise reject.

Interpretation

For the camera data, when the average incoming quality level is 100 defectives per million, the average number of lenses inspected per lot is 612.3, 500.1, and 444.7, when the sample sizes are 100, 150, and 200 and the critical distance is 3.44914. When the average incoming quality level is 600 defectives per million, the average number of lenses inspected per lot is 2815.1, 3007.3, and 3142.0, when the sample sizes are 100, 150, and 200 and the critical distance is 3.44914.