Keith M. Bower

My apologies, however new papers can only be accessed by non-ASQ or ISSSP members by following the links indicated in earlier responses. I ensure copyright permission to reproduce papers on the website as part of the deal I make with prospective publishers, for precisely that reason.
As my interest is devoted solely to furthering the cause of qu…[Read more]

I agree with your comments. For what it’s worth, there is a paper on this topic – “Non-Traditional MSA with Continuous Data”.Best wishes,-Keith

Hello David,
FYI, I submitted a paper yesterday called “Some Comments on Capability Analysis and Non-Normal Data”. Hopefully it’ll be up on my website in a month or so. I’ll be adding an appendix to the reproduced copy on my site to show exactly how I came up with the results (step by step in mtb). I’ll respond to this message again when it’…[Read more]

I agree entirely, Robert.
A key concern that I appear to share with Sheri regards control charting in a sector where there is an opportunity to take large subgroup sizes whereby the “chaff” may be hidden among the “wheat”. By this I mean that folks can hide bad values within, say, the mean. I’m keener on looking at individual values within an i…[Read more]

Incidentally, Release 14 rounds up for the number of distinct categories, unlike before. For what it’s worth, I prefer looking at the table of variance decomposition (because that table adds up to 100%).
 With regard to GR&R studies, you may find the papers at http://www.keithbower.com/KeithBower.com/SQA.htm useful – especially if you’re co…[Read more]

You’re absolutely right – the sample size calculator you mention appears to have a power value of 0.50. That means there will only be a .5 probability of you correctly rejecting the null hypothesis. That’s not high enough for most folks (certainly not me!).
For information on using Power and Sample Size for the 1-sample t-test, inlcuding an…[Read more]

For what it’s worth, “Statistical Rules of Thumb” by Gerald van Belle encourages the use of 2 sided alternative hypotheses when performing clinical trials (pp 14-16). This seems intelligent to me – when teaching, I use the allegory of crossing the road. Unless it’s a one-way system, I look in both directions to avoid being hit.
A key concern in…[Read more]

My guess is that they will be requesting an inspection of the distribution to assess whether the normal distribution is an adequate fit, with an eye to process capability estimates. 
As has been discussed in Quality Engineering (see Somerville & Montgomery, 1996), and elsewhere, capability estimates such as Cp and Cpk are highly sensitive to t…[Read more]

Fear not, – it shall be there soon, I guarantee it!  Currently, we’re just sorting out one graphic (the nested structure) before it goes on the website. Sorry for the delay….
-Keith