Complete the following steps to compare multiple sampling plans to determine the effects of varying sample size or acceptance criteria. For example, compare your current sampling plans to competing plans.
- From the drop-down, select Compare User Defined Sampling Plans.
- In Units for quality levels, select Percent defective, Proportion defective, or Defectives per million to represent the level of defectives in the process.
- In Acceptable quality level (AQL), enter a number to represent the highest defective rate from a supplier's process that is considered acceptable. You want to design a sampling plan that accepts a particular lot of product at the AQL most of the time.
The AQL must be less than the RQL.
- In Rejectable quality level (RQL or LTPD), enter a number to represent the highest defective rate that the consumer is willing to tolerate in an individual lot. You want to design a sampling plan that rejects a particular lot of product at the RQL most of the time.
The RQL must be greater than the AQL.
- In Sample sizes, specify the sample sizes that you want to compare in multiple sampling plans. In Critical distances (k values), specify the critical distances that you want to compare in multiple sampling plans.
- Specify one sample size and several critical distances to consider the effect of varying critical distances.
- Specify multiple sample sizes with just one critical distances to consider the effect of varying sample size.
- Specify combinations of sample size and critical distance to consider specific paired combinations. Use the same number of sample sizes and critical distances.
- Optional: In Lot size, enter a number to represent the lot size or batch size of the entire shipment that you will accept or reject. You don't need to specify a lot size if you specify the AQL, RQL, and alpha and beta risks. However, Minitab requires the lot size to calculate the AOQ curve and the ATI curve.