Specify the options for Variables Acceptance Sampling (Create/Compare)

Stat > Quality Tools > Acceptance Sampling by Variables > Create/Compare > Options

Enter additional quality levels to calculate acceptance probabilities: Enter defective quality levels for Minitab to calculate corresponding acceptance probabilities, using the appropriate units.; By default, Minitab displays the probability of acceptance for the AQL and RQL. You can also specify additional quality levels at which to calculate the probabilities of acceptance. For example, suppose the units for the quality level are Proportion defective. If the AQL is 0.001 and the RQL is 0.025, you may also want to investigate the probabilities of acceptance at the 0.005 and 0.01 quality levels.

Calculate the maximum standard deviation with the Wallis procedure

Minitab enables this check box when you enter a value for both Lower spec and Upper spec, but do not enter a value for Historical standard deviation. Select this option to use the approximation procedure proposed by Wallis to calculate the maximum standard deviation. For more information on the Wallis procedure, go to Methods and formulas for Variables Acceptance Sampling (Create/Compare), select Sample size and critical distance, and scroll to the section titled "Double specification limits and unknown standard deviation (Wallis procedure)".

You can make this option the default choice by going to File > Options > Control Charts and Quality Tools > Other and selecting Calculate the maximum standard deviation with the Wallis procedure (for double spec limits with unknown standard deviation case only).