Ron Manubay

Hi Johnny, No problem. I’m glad to be of help.Ronnie

Hi Johnny,Let’s take this example to illustrate what I meant. This would be long so bear with me.In a manufacturing process, you normally take some quality measurements and compare it to your spec. limits. Right? Let’s say that these measurements form a normal distribution, characterized by a mean and a standard deviation.Let’s assume further that…[Read more]

Hi IN,If I were you, I would first try to understand why my process is unstable. A simple multi-vari experiment will help you determine where the instability is coming from. What you do is to look at all the lots or units that you’ve processed in the past and plot it againts time. Look for non-random patterns, clustering, any abnormality in the…[Read more]

Hi GR,I think that part of the confusion in learning statistics and the Six Sigma concept introduced by Motorola, is the fact that the meaning of SIGMA differs between the two.Joe has given you an excellent description of what SIGMA is as a statistical term. It is – standard deviation or simply, the average deviation of each data in your sample…[Read more]

Since you have different t-test formula for equal and unequal variance, I would say that YES, it would be good to do f-test first.

What it actually gives you is the info whether your gauge is still capable of detecting the normal variations in your process. This is important for continuous improvement. As your process improves (variation decreases), there may be a time when your current gauge may no longer detect the shift or improvement in your process since it is already…[Read more]

newb,You did not mention what’s causing your unacceptable G&R. Is it due to the equipment or the appraiser? Anyway, here’s some general guidlines you can use.I would assume that you are measuring the ink size here. So my comment is based on this assumption.What I would do is to get repeated measurements and get the average as your reading. It will…[Read more]