Quality Control & Improvement Edition Improve your products and services with statistical process control (SPC).

Shewhart variable charts

• Xbar-R
• Xbar-S
• Xbar
• R
• S
• I-MR
• I
• MR

Time-weighted charts

• CUSUM
• UWMA
• EWMA

Shewhart attribute charts

• p
• np
• c
• u
• Rulesets to detect out-of-control situations: WECO, Nelson, Montgomery, Custom
• Apply control limits for each phase/stage
• Color points to identify stratification
• Label out-of-control points
• Various plot styles: Point, Line, High-Low, Boxplot

• Capability indices (Cp, Cpl, Cpu, Cpk, Cpm)
• Performance indices (Pp, Ppl, Ppu, Ppk)
• Z-benchmark
• Nonconforming units
• Histogram with specification limits
• Normal Q-Q plot
• Box-Cox and other transformations to normality

• Pareto chart
• 1-way and 2-way comparative Pareto charts
• Combine bars to reduce clutter of small occurring problems
• Reorder and vary color of bars to highlight most important problems

Continuous

• Sum, Mean, Variance, SD, CV%, Skewness, Kurtosis
• Geometric Mean, Harmonic Mean new in v4.50
• Median, Minimum, Maximum, Range, IQR
• Quantiles
• Mode
• Transform variable new in v5.50
• Histogram with optional normal overlay
• Frequency polygon
• Dot plot – jittered, aligned, spread points and vary point symbol/color
• Skeletal box plot, Tukey outlier box plot, Quantile box plot
• Mean error bar plot, Mean confidence diamond plot
• CDF plot with optional Kolmogorov-Smirnov confidence band
• Normal Q-Q plot with optional Lilliefors confidence band
• Shapiro-Wilk, Anderson-Darling, and Kolmogorov-Smirnov tests for normality
• Z test for mean with known population SD
• Student’s one sample t-test for mean
• Wilcoxon test for mean/median
• Sign test for median
• X2 test for variance
• Mean estimate with t-based or Z-based confidence interval
• Median with Thompson-Savur confidence interval
• Hodges-Lehmann pseudo-median with Tukey confidence interval
• Variance with X2-based confidence interval

Discrete

• Frequency table – frequency, cumulative frequency, relative frequency, cumulative relative frequency
• Frequency bar plot with optional cumulative frequency line
• Frequency pie (whole-to-part) plot
• Binomial exact test for proportions
• Score Z test for binomial proportions
• Pearson X2 and Likelihood ratio G2 test for multinomial proportions
• Proportion with Clopper-Pearson exact or Wilson score confidence interval

• Descriptive statistics by group
• Side-by-side dot plots, mean plots, box plots by group
• Z test for difference in means with known population SDs
• Student’s independent samples t-test for difference between means
• Welch’s t-test for difference between means with unequal variances
• Wilcoxon-Mann-Whitney test for difference between means/medians
• 1-way between-subjects ANOVA for equality of means
• Welch’s ANOVA for equality of means with unequal variances
• Kruskal-Wallis test for equality of mean/medians
• Mean difference with t-based, Welch-Satterthwaite t-based, or Z-based confidence interval

• Cohen’s and Hedge’s g standardized mean difference with non-central t-based confidence interval
• Hodges-Lehmann location shift with Moses confidence interval
• Multiple comparisons procedures: Student’s t (individual comparisons), Tukey-Kramer (all pairs), Dunnett (against control), Hsu (with best), Scheffe (all contrasts), Steel (non-parametric against control), Dwass-Steel-Critchlow-Fligner (non-parametric all pairs), Wilcoxon (non-parametric individual comparisons)
• Mean-Mean scatter plot for multiple comparisons
• F-test for variance ratio
• Bartlett, Levene, and Brown-Forsythe tests for homogeneity of variances

• Descriptive statistics for each group
• Side-by-side dot plots, mean plots, box plots by group
• Difference plot with identity line and optional histogram of differences
• Z-test for difference in means with known population SDs
• Student’s paired samples t-test for difference between means
• Wilcoxon signed ranks test for difference between means/medians
• Sign test for difference between medians

• 1-way within-subject ANOVA for equality of means
• Friedman test for equality of medians
• Mean difference with t-based or Z-based confidence interval
• Cohen’s and Hedge’s g standardized mean difference with non-central t-based confidence interval
• Median difference with Thompson-Savur confidence interval
• Hodges-Lehmann location shift with Tukey confidence interval

• Contingency table
• Grouped frequency plot
• Stacked frequency plot
• Pearson X2 test for independence / equality of proportions
• Likelihood ratio G2 test for independence
• Mosaic plot for association with color by category or residual

2x2 related tables

• McNemar-Mosteller exact test for symmetry / marginal homogeneity
• Score Z test for difference between proportions
• Proportion difference (risk difference) with Newcombe score or Tango score confidence interval
• Odds ratio with Binomial exact or Wilson score confidence interval

2x2 tables

• Fisher exact test for independence
• Score Z test for difference between proportions
• Proportion difference (risk difference) with Miettinen-Nurminen score, Newcombe score, or Tango score confidence interval
• Proportion ratio (risk ratio) with Miettinen-Nurminen score or Newcombe confidence interval
• Odds ratio with Hypergeometric exact or Miettinen-Nurminen score confidence interval

Linear Fits

• Simple linear regression
• Polynomial regression (2nd to 6th order)
• Logarithmic regression
• Exponential regression
• Power regression
• Probit regression new in v5.50
• Multiple linear regression
• ANOVA new in v4.80
• ANCOVA new in v4.80
• Advanced models with simple, crossed, polynomial and factorial terms, with categorical explanatory variables coded as dummy variables
• Transform X and Y variable in simple regression new in v5.50

Other Fits

• Binary logistic regression

• Model equation
• Summary of fit – R2, AIC, BIC
• Parameter estimates – beta, confidence intervals, VIF, standardized beta
• Scatter plot with fit line and optional confidence bands
• F-test effect of model
• Predicted against actual plot
• F-test effect of each term in model
• Leverage plot for effect of each term
• Residual plot – raw, standardized
• Sequence and Lag-1 plots
• Outlier and Influence plot
• Cook's D influence
• Predict Y for X
• Effect means for categorical variables new in v4.80
• Main effect and interaction plots for categorical variables new in v4.80
• Multiple comparisons of effect means: Student’s t (individual comparisons), Tukey-Kramer (all pairs), Dunnett (against control), Hsu (with best), Scheffe (all contrasts) new in v4.80
• F-test for lack of fit test for simple regression models
• Save model variables back to the dataset: Fitted Y, Residuals, Standardized Residuals, Studentized Residuals, Leverage, Cook's Influence

• Correlation matrix with color map on coefficients
• Covariance matrix
• Scatter plot
• Scatter plot matrix
• Vary points by color of based on a factor

Correlation / Association

• Pearson r correlation coefficient with Fisher’s Z confidence interval
• Pearson test for linear association
• Spearman rs correlation coefficient with Fisher’s Z confidence interval
• Kendall tau correlation coefficient with Samara-Randles confidence interval
• Kendall test for monotonic association

Item reliability new in v4.80

• Cronbach’s alpha (standardized and unstandardized)
• Deleted Cronbach’s alpha for each item

PCA new in v3.80

• Eigenvalues / Eigenvectors
• Coefficient matrix with color map to reveal relationships
• Classic Gabriel bi-plot with variables as vectors and observations as points
• Gower-Hand bi-plot with variables and observations as points
• Predict new observations / variables
• Reflect, rotate, and scale bi-plot
• Correlation mono-plot to show relationship between variables
• Scree plot

Common Factor Analysis new in v3.90

• Maximum likelihood factor extraction
• Factor pattern / structure matrices with color map to reveal structure
• 12 factor orthogonal/oblique rotations including Varimax, Oblimin