# Enhanced Statistical Features in SPAYN Version 1.7.2

Introduction

When performing statistical analyses it is often necessary to compute transformations
of the observed data. This transformation may only involve a single parameter,
or it may be a complicated function of several different variables. * SPAYN*
has a new feature for generating user-defined parameters as functions of existing
variables and/or constants.

A new Factor plot option allows the user to plot the percentage of explained variation versus the number of factors, for a given Principal Components or Factor Analysis. It is extremely useful to have a graphical representation of the contribution each factor makes to explaining the variance in the original data. In particular when deciding how many independent factors to utilize in further calculations.

The

*simulation interface currently generates worst-case and Monte Carlo models that can be simulated directly with an external simulator such as*

**SPAYN***The new*

**SmartSpice.***interface generates these models utilizing*

**SPAYN /SABER***simulator syntax. Thus providing the flexibility of several different external simulator options.*

**SABER**

Variable Transformation

It is frequently the case when analyzing data that some form of variable transformation
is required prior to performing any calculations. Alternatively an modeling
engineer may be interested in a particular parameter that is extremely difficult
to measure, but can be computed in terms of easily measurable variables. * SPAYN*
now has the capability to generate new parameters as functions of existing variables
and/or user-defined constants. Once the new parameter has been computed it can
be saved as a standard

*variable and treated as such for further calculation or analysis.*

**SPAYN**The Variable Transformation function is available in the Parameter Matching Window, which is accessed by clicking on Analysis->Matching... from the main

*window. Parameters P1 and P2 can then be chosen using the two pulldown menus and the scrolled Matching Quantity Window is utilized to select the required transformation function. The transformation may also only involve P1 and a constant. The Generate button will then compute the new variable, and on successful completion a histogram will appear in the graphics window. Pressing the store button allows the new parameter to be saved as a standard*

**SPAYN***variable. The following example demonstrates the full capabilities of this feature.*

**SPAYN**

Example**
** Consider constructing the new variable:

**i.** Select *P1 = PHI,* toggle the Parameter Matching
quantity sqrt(P1), press

the generate button and store the new variable as *TMP1*

**ii.** Select *P1 = VBS* and *P2 = TMP1,* toggle
the Parameter Matching quantity

P1/P2, press the generate button and store the new variable as *TMP2.*

**iii.** Select *P1 = TMP2* and Constant = 5.24, toggle
the Parameter Matching quantity

*P1+P2,* press the generate button and store the new variable as TMP3.

**iv.** Select *P1 = GAMMA* and *P2 = TMP3,* toggle
the Parameter Matching quantity

*P1*P2,* press the generate button and store the new variable as TMP4.

**v.** Select *P1 = VBI* and *P2 = TMP4,* toggle
the Parameter Matching quantity P1+P2,

press the generate button and store the new variable as *VTH* as required.