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Statistical Analysis Software for Environmental Data

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Environmental Statistical Analysis Software Solution for Windows

ChemStat is the easiest and fastest application available for the statistical analysis of ground water monitoring data at RCRA facilities. ChemStat includes most statistical analysis methods described in the 1989 and 1992 USEPA statistical analysis documents, USEPA Draft Unified Guidance Document, U.S. Navy Statistical Analysis Guidance document, and other guidance documents and methods documented in popular statistical texts.

A unique combination of ease-of-use and innovative technologies make ChemStat the value leader for environmental statistical analysis.

Browse the help system to learn more.

Download ChemStat Trial Version (Version 6.5 Now Available)

ChemStat Frequently Asked Questions

New Features for v. 6.5 (Available January, 2023):

  • Upper confidence limit (UCL) calculations for all wells using a variety of statistical methods
  • Improved user interface
  • Improved support for the latest versions of Windows

New Features for v. 6.4 (Available July, 2016):

  • New Shewhart-CUSUM Control Chart follows "non-standardized" method of USEPA Unified Guidance

New Features for v. 6.3 (Available December 20, 2010):

  • Tarone-Ware Two-Sample Test - A non-parametric test comparable to the Wilcoxon presented in the USEPA Unified Guidance.

New Features for v. 6.2 (Available April 1, 2007):

  • Non-Parametric Confidence Limit MCL Comparison.
  • Parametric Prediction Limit (inter-well) with verification resampling as described in USEPA Unified Guidance, for the following resampling schemes:
    • 1 of 2
    • 1 of 3
    • 1 of 4
    • Modified California

New Features for v. 6.1 (Available March 25, 2006):

  • Export Workbook reports and graphs directly into Microsoft Word.
  • Improved Workbook printing to Acrobat PDF files.

New Features for v. 6.0 (Available July 23, 2005):

  • New methods for compliance with USEPA Draft Unified Guidance:
  • Rank von Neumann test
  • Spearman's Trend Test
  • Welch's t-test
  • New features for adjustment of data (add/remove samples based on date ranges, parameter names, well IDs)
  • Improved Prediction Limits
  • Improved Control Chart
  • Improved Probability Plot
  • Improved Graphs and Reports

New Features for v. 5.2:

  • New Upper Confidence Limit (UCL) Methods Including:
  • Student's t-test UCL Method
  • Chebyshev Inequality UCL Method
  • Central Limit Theorem UCL Method
  • Bootstrap Resampling UCL Method
  • Jackknife Procedure UCL Method
  • Improved Probability Plot for Censored and Detects-Only Plots

New Features for v. 5.0:

  • Improved graph vertical axis scaling
  • Method Selector Tree -- Hierarchical tree simplifies the selection of the appropriate statistical tests.
  • Poisson Prediction Limit not available as intra-well comparison
  • New statistical methods, including methods from U.S. Navy (1999) statistical guidance documents.
  • Improved Parametric t-test
  • Satterthwaite t-test
  • Quantile Non-Parametric test
  • Two Sample Test of Proportions MCL Comparison
  • Slippage Non-Parametric test
  • Improved Wilcoxon test for group comparisons (following U.S. Navy Guidance)
  • Discordance Outlier Test
  • Enhanced parametric t-test follows U.S. Navy (1999) Guidance

New Features for v. 4.1:

  • Parametric t-test analysis.
  • Confidence interval analysis by Land's formula for log-normal data.
  • Two-tailed parametric tolerance limits

New Features for v. 4.0:

  • Fully automated statistical analysis -- perform a complete statistical analysis of an entire data set with a single command.
  • Batch Processing -- Automated statistical analysis with scripts (create a script of commands for a list of parameters and perform all commands at once).
  • Direct import of SanitasĀ® and DUMPStatĀ® databases.
  • Improved support for different parameter units.
  • Automatic elimination of outliers.
  • Mann-Kendall supports testing for upward, downward, or two-tailed trends.

New Features for v. 3.0:

  • Easier File Importing -- File importing has been simplified.   Preview the file to prevent formatting mistakes.
  • Summary List summarizes of all wells showing statistically significant contamination for your project, showing parameter name, transformation, and statistical method.
  • More Transformations -- In addition to natural logarithm transformations, you can choose log base 10, square root, or cube root transformations.
  • Probability Plot Correlation Coefficient

ChemStat Features

ChemStat is powerful
Data set size limited only by computer memory for most tests
Unlimited number of parameters
Unlimited number of wells
Unlimited number of sample dates
Unlimited parameter name and well label length
Easily exclude individual data points from analyses
Fast Performance
Full report and graph printing and print preview
Export reports to tab-delimited ASCII text file
Export reports to a word processor in rich-text format
Numerous choices for page headers and footers, page left, right, and center
Choice of multiple fonts and colors in graphs and reports
Highly customizable user-interface
ChemStat is easy to learn
Easily select parameter for analysis from drop-down list
Complete on-line help with "what's this" context sensitive help.
Advisor Window displays information about the method and suitability of the method to the data set.
Method selector tree allows easy selection of the appropriate statistical test for your data
Data Set Transformations
Quickly convert from original data to log-transformed and back
Easily represent non-detects with 0, 1, DL/2 or DL for any test
Accommodate censored data with Cohen's or Aitchison's adjustments

ChemStat Analysis Methods

bullet Box/Whisker Plots
bullet Single Well Concentration vs. Time Plot
bullet Multiple Well Concentration vs. Time Plot
bullet Multiple Parameter Concentration vs. Time Plot
bullet Probability Plots
bullet Shewhart-CUSUM Control Chart for both Intra-Well or Inter-Well Comparison
bullet Exponentially Weighted Moving Average Control Chart for both Intra-Well or Inter-Well Comparison
bullet Parametric Methods
bullet Parametric ANOVA with Individual Well Comparisons
bullet Parametric Prediction Limit (intra-well or inter-well comparison)
bullet Parametric Tolerance Limit (comparison to background)
bullet Parametric Tolerance Limit (comparison to MCL)
bullet Parametric Confidence Interval
bullet Parametric t-test
bullet Satterthwaite t-test
bullet Welch's t-test
Non-Parametric Methods
bullet Kruskal-Wallis Non-Parametric Analysis
bullet Wilcoxon Rank-Sum Non-Parametric Analysis (intra-well comparison)
bullet Wilcoxon Rank-Sum Non-Parametric Analysis (inter-well comparison)
bullet Poisson Prediction Limit
bullet Poisson Tolerance Limit (comparison to background)
bullet Poisson Tolerance Limit (comparison to MCL)
bullet Non-Parametric Prediction Limit (intra-well or inter-well comparison)
bullet Non-Parametric Confidence Limit
bullet Gehan's Test
bullet Slippage Test
bullet Quantile Test
bullet Two Sample Test of Proportions MCL Comparison
Distribution/Outlier/Trend Testing
bullet Levene’s Test for Homogeneity of Variance
bullet Bartlett’s Test for Homogeneity of Variance
bullet Shapiro-Wilks Test of Normality
bullet Shapiro-Francia Test of Normality
bullet Coefficient of Variation Test of Normality
bullet D'Agostino's Test of Normality
bullet Skewness Coefficient Test
bullet Dixon's Test for Outliers
bullet Rosner's Test for Outliers
bullet Discordance Outlier Test
bullet Mann-Kendall Test for Trend
bullet Spearman's Test for Trend
bullet Sen's Slope Analysis for Trend
bullet Seasonal Kendall Analysis
bullet Kurtosis

ChemStat Screen Shots
Click on an Image to View Full Size

anova.gif (37408 bytes) Among the methods for inter-well comparisons are the parametric analysis of variance ANOVA as shown here, as well as Kruskal-Wallis and Wilcoxon non-parametric comparisons.
cusum.gif (23442 bytes) ChemStat include a powerful and highly customizable Shewhart-CUSUM control chart, for both inter-well and intra-well comparisons.
multprm.gif (24636 bytes) Shown here is the multiple parameter time-series plot.  Graph any combination of parameters for a single well.
multwell.gif (19459 bytes) Shown here is a multiple well time series plot.  Graph any combination of wells for a selected parameters.  ChemStat spaces the date axis proportional to the actual date value of the sample.  ChemStat also plots multiple concentrations for a single date.
predlmt.gif (20234 bytes) New:  ChemStat 2.0 includes improved prediction limits. Verification resampling is supported by allowing you to vary the number of samples for each well compared to the prediction limit.  Parametric prediction limit calculations can follow USEPA (1989), Gibbons (1987) one-sided, or Gibbons (1987) two-sided algorithms.
windows.gif (24661 bytes) Here is another view of ChemStat showing Skewness calculations, probability plot, and the Workbook.
workbook.gif (31880 bytes) The Workbook acts as a repository for all your reports and graphs.  Workbook items are saved with your data, and will not change as you apply transformation to the data set.  When you have completed your statistical analysis, you can print the entire workbook, or selected items.
outlier.gif (31454 bytes) ChemStat 2.1 adds the ability to easily exclude individual samples from statistical analyses, and then add them back at a later date.  This is useful for removing statistical outliers, or reducing the size of the data set for an individual well or background wells.
methodtreescreen.GIF (34641 bytes) New: ChemStat 5.0 adds the Method Selector Tree.  The method selector tree simplifies the selection of appropriate statistical methods.  Methods are grouped into a logical hierarchy.  Double-click a method to run the test.

System Requirements: Windows 7 or later, 8 GB RAM recommended minimum.

No "Per Facility" Fees

A Complete Data Management and Statistical Analysis Package for Windows