• Thanks for your response,
    I am using median-range charts and subgroup size is three pieces. I am using SPC second edition formulas on page 85, but I am calculating capabilty index with average-range formulas. I am not using median-moving range charts. I have Minitab 13.
    Is it the correct way for doing it? Thanks.

    JCastillo 9 years, 9 months ago