We are involved in a company project to understand whether the samples we take are taken correctly (according to the Theory of Sampling). We produce animal feeds in our mills as separate batches (with each batch usually being very different to each other in terms of their analysis) and sampled at a point below the mixer.
We have been introduced to Variograms by a geologist and I am attempting to apply this technique to our quality sampling and analysis of our feeds and raw materials – to test the “spatial correlation” or complete lack of it – i.e. should we give up sampling at that point at all?
I have been trying to understand what the Variogram is attempting to measure and its practical application to our processes. I also understand that the Variogram is just the first step, the second (assuming I need to move to this) being using this information for use in the Kriging model.
Looking at some real life Variograms it appears that calculation of the Nugget, and Sill/Range is a subjective determination especially if the curve is wavy (periodicity or not?) and then whether it should be spherical or exponential etc.
So my first query is whether the Variogram model is at all valid for our process and if so does JMP have software tools for this and is further modelling i.e. Kriging of use? And if this isn’t applicable are there other JMP statistical models to answer the question “should we give up sampling at that point at all”. Hope all this makes sense. I have JMP Standard. Thank you.
