# Useful Statistical Tools

## Quick Parameter Estimator (QPE)

The Quick Parameter Estimator (formerly called the "Parameter Experimenter") has been redesigned and expanded in the Synthesis version. The QPE allows you to estimate the parameters of a statistical model based on what you know about the behavior over time. Now you can now estimate the parameters of the entire model, including both the life-stress relationship and the use-level life distribution (e.g., Arrhenius-Weibull or Eyring-Lognormal). We have also added support for models with more than one accelerated stress type (e.g., Temperature-Humidity or General Log-Linear).

## Quick Statistical Reference

The Quick Statistical Reference frees you from tedious lookups in tables by quickly returning results for commonly used statistical functions. Results include Median Ranks, Chi-Squared Values, Cumulative Binomial Probability, and many more. There is also a Polynomial Interpolation Function that allows you to enter known data points and then calculate Y for any given X value.

## Non-Linear Equation Fit Solver and Root Finder

The software continues to offer two familiar statistical tools for working with non-linear equations.

• Redesigned with a more user-friendly interface, the Non-Linear Equation Fit Solver allows you to estimate the parameters of any user-defined non-linear equation. This gives you the flexibility to perform simple parameter estimation on statistical models other than the life distributions and life-stress relationship models available in standard folios. After you have solved the equation, the tool provides a plot to visualize how the data fit the function, and also makes it easy to calculate Y for any given X value.
• The Non-Linear Equation Root Finder allows you to quickly solve for the root of any user-defined non-linear equation. This helps you eliminate some of the guesswork of solving for the value of the unknown variable that makes the function be as close to zero as possible.
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