Originally posted by narfeldt:
My problem is how to get a graph with normal distrubution. The graph should illustrate a straight curve then the process is normal distrubated. I don't know what it's name are for this in your countries, but in sweden we call it normal distrubution paper.
I have seen normal probability paper shown in several references, but I have never seen the paper itself. (The x axis is in sigma, and the y axis is in median rank. Each axis is scaled so that if an exact gaussian "normal" curve is plotted the result is a straight line.) (Does anyone know of a source?)
I have not seen a way to do that in Microsoft Excel - and I just checked a big book on formulas and macros again to be sure. Lots of histograms and curves, but no normal probability plots. This may be because Excel is optimized for general-purpose business applications and does not have many technical or statistical features.
On the occasions where I have needed to use this kind of graph, I have imported the data into a statistical analyis and graphics program. (I use StatMost; there are other good ones as well.) I would think that most statistical analysis programs have this kind of plot as a standard feature -- they are specialized for this kind of work. If you don't have such a program readily available I think it is a good idea to get one.
------------------
Graeme C. Payne
ASQ Certified Quality Engineer
[email protected]
