The curve fitting platform allows you to select from a library of model types.
In this post I take a closer look at the different model types that are available to support curve fitting.
Category Archives: Statistics
The Lognormal Distribution
The lognormal distribution is a commonly used distribution for modelling asymmetric data. It’s just the log of a Normal distribution right? Well no, it’s actually the other way around. You take the log of a lognormal distribution to arrive at a normal distribution. Is it just me, but I always have a bit of a mental block about this, it always feels a bit back to front.
In this post I will explore the relationship between a lognormal distribution and a normal distribution.
Capability Indices and Process Shift
In this post I will derive a simple relationship between process shift and the capability indices Cp and Cpk.
Visualising the Null Hypothesis
In this post I describe an approach that I use to teach statistics. The goal is to use JMP to help develop an intuitive understanding of some common concepts: hypothesis testing, p-values and reference distributions.
The Range Statistic
Quality control techniques such are control charts and Gage R&R studies sometimes feel as if they are stuck in the pre-computer age. For example they typically use range as a measure of dispersion since it is far easier to calculate than a standard deviation.(more…)
Assessing Curvature
Statistics is not about conforming to some strange protocol that we neither agree with nor like.
Notation of Model Interaction Terms
Here is a data table that I have created. It happens to contain data
that is the result of a designed experiment. I know that, but JMP doesn’t.
(more…)