Standard Deviation
Upload data or paste values to calculate mean, variance, standard deviation, range, and CV.
Open ToolAnalytical Tools
Stat-Forge Tools and Calculators
Practical statistical, engineering, SPC, capability, and MSA calculators for coursework, quality engineering, and applied process analysis. Most tools support CSV upload, example data, and direct manual entry.
Phase 1 calculator expansion
From basic statistics to advanced process monitoring
The calculator collection is organized as a practical learning path: basic statistics, quality metrics, process capability, SPC charts, and measurement-system analysis. The advanced Stat-Forge material extends this path into PCA monitoring, Tensor SPC, Tensor Q residual monitoring, and structured-data diagnostics.
Use the statistical diagnostics on this page to evaluate data quality, distribution assumptions, variance consistency, and measurement system performance before applying process monitoring, capability studies, or decision-making methods.
Basic Statistics
Confidence Interval
Upload data or enter summary statistics for a two-sided confidence interval for a mean.
Open ToolZ-Score
Calculate z-scores and normal probabilities from entered values or uploaded data.
Open ToolSample Size Calculator
Estimate sample size for means, proportions, and capability-study planning.
Open ToolProcess Capability
Process Capability Study Report
Create a capability study report with control charts, histogram, probability plot, Cp/Cpk, Pp/Ppk, PPM, and sigma estimates for individual or subgrouped data.
Open ToolCp / Cpk
Upload process measurements and select the within-sigma method used for capability.
Open ToolPp / Ppk
Upload process measurements and calculate performance capability using overall sample SD.
Open ToolCp/Cpk Confidence Intervals
Estimate Cp and Cpk with approximate confidence intervals for capability-study planning and reporting.
Open ToolSPC
Xbar-R Chart
Upload subgrouped data and calculate Xbar-R center lines and control limits.
Open ToolXbar-S Chart
Upload subgrouped data and calculate Xbar-S center lines and control limits.
Open ToolConsistency / I-MR Chart
Build an I-MR chart for sequential measurement data.
Open ToolControl Chart Rules
Screen control chart data for common run, trend, and out-of-control signals.
Open ToolAttribute Control Charts
Build p, np, c, and u charts for attribute quality data.
Open ToolMSA
Gage R&R
Upload Part, Operator, Measurement data for an initial MSA screening calculation.
Open ToolBasic EMP Study
Evaluate repeated part/operator measurements with probable error, ICC, and EMP monitor classification.
Open ToolShort EMP Study
Evaluate measurement-system discrimination with Short EMP metrics.
Open ToolProbable Error
Estimate measurement-system probable error from repeat measurements.
Open ToolAttribute Agreement Analysis
Evaluate categorical or pass/fail inspection agreement across appraisers and known standards.
Open ToolEngineering Tools
Tolerance Stack-Up Calculator
Analyze assembly tolerance using worst-case, RSS, and Monte Carlo simulation methods with contribution and distribution charts.
Open ToolGD&T Tolerance Analysis
Calculate bonus tolerance, virtual condition, allowable position tolerance, and pass/fail status for size features.
Open ToolFit & Clearance Calculator
Calculate minimum clearance, maximum clearance, allowance, and fit type for mating feature limits.
Open ToolGeometric Tolerance Calculator
Evaluate true position, profile zone width, orientation error, and runout-style geometric conditions.
Open ToolQuality Metrics
Statistical Diagnostics
Normality Test Calculator
Evaluate Anderson-Darling, Shapiro-Wilk, and Skewness-Kurtosis normality diagnostics.
Open ToolAnderson-Darling Test
Focused Anderson-Darling normality test page with example data, charts, and downloads.
Open ToolShapiro-Wilk Test
Focused Shapiro-Wilk normality test page with Q-Q plot and downloadable results.
Open ToolHomogeneity Test
Evaluate group-to-group variance and mean consistency.
Open ToolDistribution Fitting
Fit Normal, Lognormal, Weibull, Gamma, Exponential, and Uniform distributions with AIC ranking and histogram overlays.
Open Tool