This repository contains simple theoritical information that demonstrates the use of data and linear transformation techniques to clean, prepare and analyze manufacturing data for process improvement
Data transformation involves changing the format, structure, or values of data to make it suitable for analysis, modeling, or control. It is crucial in manufacturing to:
- Normalize or standardize measurements across resources
- Convert units (e.g. tons to kilograms)
- Handle non-linearity in sensor data
- Identify hidden trends or prepare data for statistical models Generally, normally distributed data is preferred in order to use a no. of statisical tools like:
- Individual value control charts
- Capability analysis
- T-Tests
- ANOVA When data is not normally distributed, the cause for non-normality should be determined and appropriate remedial actions should be taken
+-------------+ |Non-normal data| +-------------+ | v +-------------+ |Data transformation| +-------------+ | v +----------+ +-----------+ |Linear| |Box and Cox| +----------+ +-----------+ | v +---------+ |Normal data| +----------+
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A linear transformation is a specific type of data transformation where we apply a linear function to a variable, usually of the form:
Y = aX + b
- This is useful for normalizing machine measurements and simplifying multivariate analysis
- The original data is multiplied or divided by a coefficient or a constant is subtracted or added
- It does not change the shape of the data distribution
- The Box-Cosx transformation is a powerful statistical method used to stabilize variance, make data more normal, and improve the performance of predictive models - especially useful in manufacturing data that often includes skewed or non-linear patterns
- The Lambda value (λ) indicates the power to which all data should be raised
- The family of the power transformations are used for: 1. Converting a dataset to use parametric statistics 2. Any continuous data > 0
- The use of transformation will not guarantee normality
For a variable y and transformation parameter (λ):
y(λ) = {y^λ -1, if λ ≠ 0
{ ln(y), if λ = 0
"If your data isn't normal, don't fix the process - fix the scale"