To compare variables sampling plans
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1    Choose Stat > Quality Tools > Acceptance Sampling by Variables > Create / Compare.

2    Choose Compare user defined sampling plans.

3    In Units for quality levels, choose one of the unit types depending on your specific measurement.

4    In both Acceptable quality level (AQL) and Rejectable quality level (RQL or LTPD)., enter a value to specify the risk levels if you wish. It is not necessary to specify AQL or RQL when comparing sampling plans. Use the same units as you indicated above. For example, use 2 for percent defective and 0.02 for proportion defective.

5    In Sample sizes and Critical distances (k values), specify the combination of sampling parameters that you want to examine. Do one of the following:

·    Specify one sample size and several critical distances to look at the effect of just varying critical distance.

·    Specify multiple sample sizes with just one critical distance to look at the effect of just varying sample size.  

·    Specify combinations of sample size and critical distances to look at specific paired combinations.  

6    In Lower spec and Upper spec, specify the lower and upper specifications of the measurement you are evaluating. You must enter at least one of the specifications.

7    In Historical standard deviation, enter the known process standard deviation. This is optional.

8    In Lot size, enter the number of units that you are sampling from. The lot size is not required if the AQL, RQL, and alpha and beta risks are given; however, Minitab requires the lot size to calculate the AOQ curve and the ATI curve.

9    If you like, use any dialog box options, then click OK.