Assumptions
The normal distribution is NOT assumed nor required in the calculation of control limits. Thus making the IndX/mR chart a very robust tool. This is demonstrated by Wheeler using real-world data, and for a number of highly non-normal probability distributions.
Read more about this topic: Shewhart Individuals Control Chart
Famous quotes containing the word assumptions:
“What a man believes may be ascertained, not from his creed, but from the assumptions on which he habitually acts.”
—George Bernard Shaw (1856–1950)
“Assumptions of male superiority are as widespread and deep rooted and every bit as crippling to the woman as the assumptions of white supremacy are to the Negro.... this is no more a man’s world than it is a white world.”
—Student Non-Violent Coordinating Committee, African American civil rights organization. SNCC Position Paper (Women in the Movement)
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—Elaine Heffner (20th century)