Lower and Upper Fence Calculator
Introduction & Importance
Calculating lower and upper fences is crucial in statistical process control to identify out-of-control processes. It helps maintain product quality and consistency.
How to Use This Calculator
- Enter your data, comma-separated.
- Choose the desired coefficient (k) based on your required confidence level.
- Click ‘Calculate’.
Formula & Methodology
The lower fence is calculated as X̄ – k * s, and the upper fence as X̄ + k * s, where X̄ is the mean and s is the standard deviation.
Real-World Examples
Case 1: Product Weight
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Data & Statistics
| Coefficient (k) | Confidence Level |
|---|---|
| 1.645 | 90% |
| 1.96 | 95% |
| 2.05 | 97.5% |
| 2.576 | 99% |
Expert Tips
- Always use a representative sample size.
- Consider using a normal probability plot to check data normality.
Interactive FAQ
What is the difference between lower and upper control limits?
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