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Changing doc to reflect revised constructor for SimpleRegression 

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/math/trunk@1167460 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Greg Sterijevski 2011-09-10 05:20:56 +00:00
parent 99458101a5
commit 25acfb6505
1 changed files with 33 additions and 2 deletions
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35
src/site/xdoc/userguide/stat.xml
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@ -365,6 +365,10 @@ System.out.println(f.getCumPct("z")); // displays 1
<code> y = intercept + slope * x </code> <code> y = intercept + slope * x </code>
</p> </p>
<p> <p>
or
<p>
<code> y = slope * x </code>
</p>
Standard errors for <code>intercept</code> and <code>slope</code> are Standard errors for <code>intercept</code> and <code>slope</code> are
available as well as ANOVA, r-square and Pearson's r statistics. available as well as ANOVA, r-square and Pearson's r statistics.
</p> </p>
@ -408,7 +412,6 @@ System.out.println(f.getCumPct("z")); // displays 1
Here are some examples. Here are some examples.
<dl> <dl>
<dt>Estimate a model based on observations added one at a time</dt> <dt>Estimate a model based on observations added one at a time</dt>
<br></br>
<dd>Instantiate a regression instance and add data points <dd>Instantiate a regression instance and add data points
<source> <source>
regression = new SimpleRegression(); regression = new SimpleRegression();
@ -445,8 +448,8 @@ System.out.println(regression.predict(1.5d)
More data points can be added and subsequent getXxx calls will incorporate More data points can be added and subsequent getXxx calls will incorporate
additional data in statistics. additional data in statistics.
</dd> </dd>
<br></br>
<dt>Estimate a model from a double[][] array of data points</dt> <dt>Estimate a model from a double[][] array of data points</dt>
<br></br>
<dd>Instantiate a regression object and load dataset <dd>Instantiate a regression object and load dataset
<source> <source>
double[][] data = { { 1, 3 }, {2, 5 }, {3, 7 }, {4, 14 }, {5, 11 }}; double[][] data = { { 1, 3 }, {2, 5 }, {3, 7 }, {4, 14 }, {5, 11 }};
@ -468,6 +471,34 @@ System.out.println(regression.getSlopeStdErr());
More data points -- even another double[][] array -- can be added and subsequent More data points -- even another double[][] array -- can be added and subsequent
getXxx calls will incorporate additional data in statistics. getXxx calls will incorporate additional data in statistics.
</dd> </dd>
<br></br>
<dt>Estimate a model from a double[][] array of data points, <em>excluding</em> the intercept</dt>
<dd>Instantiate a regression object and load dataset
<source>
double[][] data = { { 1, 3 }, {2, 5 }, {3, 7 }, {4, 14 }, {5, 11 }};
SimpleRegression regression = new SimpleRegression(false);
//the argument, false, tells the class not to include a constant
regression.addData(data);
</source>
</dd>
<dd>Estimate regression model based on data
<source>
System.out.println(regression.getIntercept());
// displays intercept of regression line, since we have constrained the constant, 0.0 is returned
System.out.println(regression.getSlope());
// displays slope of regression line
System.out.println(regression.getSlopeStdErr());
// displays slope standard error
System.out.println(regression.getInterceptStdErr() );
// will return Double.NaN, since we constrained the parameter to zero
</source>
Caution must be exercised when interpreting the slope when no constant is being estimated. The slope
may be biased.
</dd>
</dl> </dl>
</p> </p>
</subsection> </subsection>