Quality Stat is a collection of practical statistical and quality engineering tools designed to help engineers analyze quality data and turn statistical results into meaningful engineering decisions.
Quality Stat is available as a web application built with Streamlit.
Live application: Quality Stat
The first version of Quality Stat focuses on Process Capability Analysis, with particular emphasis on:
- Cp — Potential Process Capability
- Cpk — Actual Process Capability
- Cpu — Upper Specification Capability
- Cpl — Lower Specification Capability
- Process mean and variation
- Capability assessment
- Engineering interpretation
- Process capability histogram
The project combines calculation tools with engineering explanations so that users can understand not only the numerical result, but also what the result means.
The Cp/Cpk Calculator evaluates process capability using measured process data and engineering specification limits.
- Lower Specification Limit (LSL)
- Target
- Upper Specification Limit (USL)
- Measured process values
The calculator provides:
- Sample size
- Process mean
- Standard deviation
- Observed range
- Cp
- Cpk
- Cpu
- Cpl
- Capability assessment
- Engineering interpretation
- Process capability histogram
Quality Stat also includes a dedicated theory reference covering:
- Process capability
- Specification limits
- Process variation
- Process mean
- Cp
- Cpk
- Cpu and Cpl
- Cp vs Cpk
- Process centering
- Limiting specification side
- Capability interpretation
- Worked example
- Important assumptions
- Common mistakes
- Cp/Cpk vs Pp/Ppk
- Quick reference
The application is built using:
- Python
- Streamlit
- Pandas
- Matplotlib
The project is organized so that calculation logic is separated from the Streamlit user interface.
Quality_Engineering_Website/
│
├── calculations/
│ ├── capability.py
│ └── interpretation.py
│
├── pages/
│ ├── 1_📊_Cp_Cpk_Calculator.py
│ └── 2_📘_Cp_Cpk_Theory.py
│
├── _example_data.py
├── app.py
├── requirements.txt
├── .gitignore
└── README.md