Complete the following steps to determine whether to accept or reject an entire lot based on your measurement data and your specifications.
- In Measurement data, enter the column that contains the measurement data.
- In Critical distance (k value), enter the value that Minitab uses to compare with the sample mean and specification limits to determine whether to accept a or reject a sampled lot. Minitab calculates this value when you create a variables acceptance sampling plan.
- In Lower spec, enter the lower specification limit. You must enter at least one specification limit.
- In Upper spec, enter the upper specification limit. You must enter at least one specification limit.
- Optional: In Historical standard deviation, enter the known standard deviation of your process. Use a historical standard deviation when you have collected enough data over time to state with confidence what the process standard deviation is.
- Optional: Minitab enables the check box for Calculate the maximum standard
deviation with the Wallis procedure 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 Calculate the maximum standard deviation with the Wallis
procedure (for double spec limits with unknown standard deviation case