Probability paper
This probability paper is not only a didactic instrument, but it can also be used for day-to-day controls. Comatech has 2 types of probability papers:
Normal probability paper (NPP)
Graphical test to check whether a distrubition is normal or log-normal distributed
A lot of statistic methods and calculations start from a particular form of distribution. One seldom checks whether these conditions are met. Yet it is essential to give the results any relevance. With the normal probability paper you can check whether the distribution is normal or exponential.
By drawing the cumulative function of a histogram on this paper, you can check whether this particular distribution is normal. It is manifested in a straight line upon which all checkpoints are situated. If you don't see a straight line, you can try a logaritmic scale at the bottom of the paper. If all points in this scale are in a straight line, you are dealing with an exponential distribution. With these two distributions you can solve 99% of all your problems.
Are you not yet comfortable with this technique? Consult the book Simple statistics for small series.
Advantages
- 2 different distributions on 1 paper
- At 1, 2 and 3 times the standard deviation there are bold lines to make it easier to read the matching measuring results
- In the heading you can put all useful information such as date, subject, specification,...
Prices
23 EURfor a set of 100 sheets
Binomial probability paper (BPP)
Graphic test to accept or reject hypotheses
A lot of problems on TQM topics can be solved by the so-called 'seven tools'. BPP is 1 of these 7.
Next questions may sound familiar. I have got several suppliers for one type of raw material, do they supply equivalent products? How often shall I sample to be sure not delivering too many defective products? How can I quickly compare two analysis methods? These and so many other problems can be solved with this graphic paper.
Are you not yet comfortable with this technique? Consult the book Simple statistics for small series.
Advantages
- Simple, quick and easy to use
- Decisions and results graphically presented
- Broad application area, both in industry and services
Prices
23 EUR for a set of 100 sheets
