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N-STEPS - Statistical Tools

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Fact Sheets

Fact sheets on statistical information commonly used in nutrient criteria development and links to other statistical resources.

  • Change-point analysis is a method for identifying thresholds in relationships between two variables.
    Change-Point Analysis Fact Sheet
  • Correlation is a measure of the strength of a relationship between two variables.
    Correlation Fact Sheet
  • Loess stands for locally estimated scatterplot smoothing (lowess stands for locally weighted scatterplot smoothing) and is one of many non-parametric regression techniques.
    Loess or Lowess Fact Sheet
  • Regression is one of the most common statistical modeling tools used, regression is a technique that treats one variable as a function of another.
    Regression Fact Sheet
  • A conditional probability is the probability of an event occurring when some other event has occurred.
    Conditional Probability Fact Sheet
  • Classification, in the nutrient criteria process, is the process of identifying groups of sites that have comparable characteristics and for which comparable nutrient behavior is expected.
    Classification Fact Sheet
  • Weighted averaging is a method for computing an average where some values receive greater weight than others.
    Weighted Averaging Fact Sheet

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Statistics Resources

Software

  • R - Widely used free software environment for statistical computing and graphics. It compiles and runs on a wide variety of UNIX platforms, Windows and MacOS.
  • R Studio - Provides a graphical interface for use with R.
  • Free Statistical Packages (BUGS, R, STATS) - Free software that will run different statistical tests.
  • University of Minnesota - Arc Software - A package for regression analysis designed as a companion to the book Applied Regression Including Regression and Graphics by R.D. Cook and S. Weisberg.
  • Statistical Analysis Tools - Analysis programs, power analysis, stats tables (t distribution, chi square, normal distribution, etc.); describes univariate data, curve fitting, and distribution-free tests.

Open Source Statistics Training

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