<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN"> <!--Converted with LaTeX2HTML 98.1p1 release (March 2nd, 1998) originally by Nikos Drakos (nikos@cbl.leeds.ac.uk), CBLU, University of Leeds * revised and updated by: Marcus Hennecke, Ross Moore, Herb Swan * with significant contributions from: Jens Lippmann, Marek Rouchal, Martin Wilck and others --> <HTML> <HEAD> <TITLE>Presentation and inspection of results</TITLE> <META NAME="description" CONTENT="Presentation and inspection of results"> <META NAME="keywords" CONTENT="vol2"> <META NAME="resource-type" CONTENT="document"> <META NAME="distribution" CONTENT="global"> <META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1"> <LINK REL="STYLESHEET" HREF="vol2.css"> <LINK REL="next" HREF="node230.html"> <LINK REL="previous" HREF="node228.html"> <LINK REL="up" HREF="node222.html"> <LINK REL="next" HREF="node230.html"> </HEAD> <BODY > <!--Navigation Panel--> <A NAME="tex2html4270" HREF="node230.html"> <IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="icons.gif/next_motif.gif"></A> <A NAME="tex2html4267" HREF="node222.html"> <IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="icons.gif/up_motif.gif"></A> <A NAME="tex2html4261" HREF="node228.html"> <IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous" SRC="icons.gif/previous_motif.gif"></A> <A NAME="tex2html4269" HREF="node1.html"> <IMG WIDTH="65" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="contents" SRC="icons.gif/contents_motif.gif"></A> <BR> <B> Next:</B> <A NAME="tex2html4271" HREF="node230.html">Parameter estimation</A> <B> Up:</B> <A NAME="tex2html4268" HREF="node222.html">Basic principles of time</A> <B> Previous:</B> <A NAME="tex2html4262" HREF="node228.html">Time domain analysis</A> <BR> <BR> <!--End of Navigation Panel--> <H2><A NAME="SECTION001727000000000000000"> Presentation and inspection of results</A> </H2> <P> A simple way to graphically present the results of a TSA is to plot the test statistics <I>S</I> against its parameter <IMG WIDTH="42" HEIGHT="54" ALIGN="BOTTOM" BORDER="0" SRC="img481.gif" ALT="$\nu$"> or <I>l</I>, depending on whether the analysis was performed in the frequency or time domain. Plots in the frequency domain are called periodograms. In them, oscillations are revealed by the presence of spectral lines. However, some (often many) lines are spurious and simply arise from random fluctuations of the signal. By means of the confidence level <IMG WIDTH="44" HEIGHT="54" ALIGN="BOTTOM" BORDER="0" SRC="img482.gif" ALT="$\alpha$">and the probability distribution of <I>S</I> one can find the critical value <I>S</I><SUB><I>crit</I></SUB> for significant features. Examples of statistics used in the time domain are covariance and correlation functions. The correlation of a signal with itself or with another signal produces maxima in these functions at particular lags. Detection of genuine lags then consists of testing the significance of such maxima. <P> <BR><HR> <ADDRESS> <I>Petra Nass</I> <BR><I>1999-06-15</I> </ADDRESS> </BODY> </HTML>
