Monthly Archives: November 2009

What’s the confidence level of sample data used for regression analysis ?

It’s a tough question to understand and answer! From my previous blog, it was shown how confidence level is determined and tied to confidence interval. Another element that governs the confidence interval limits ( upper & lower confidence limits ) … Continue reading

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What’s the confidence level of a sample data ?

From statistical view point, confidence level is one element that always tied to confidence interval. The need for confidence interval ? In most data analysis, one collect sample data ( say a parameter which data type is variable ) to … Continue reading

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Is 3 Sigma quality level good enough ?

Recently, management raised a question of what’s should be the minimum Sigma ( s ) quality level of product quality is deemed to be acceptable. One said that 6s quality level should be set as acceptable specification since the implementation … Continue reading

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How to formulate a predicted model equation ?

Recently, a big argument raised on one Six Sigma BB project. The goal of this project is to establish a model equation to predict a Response ( Y ) from a set of predictors ( Xs ) Background In this … Continue reading

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Is Six Sigma a data-driven quality strategy for process/product improvement ?

The answer is definitely YES and I am sure no one will disagree with this. If we don’t have data, we can’t measure. If we can’t measure, we have no idea how’s good of a process / product performance. This … Continue reading

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