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    <h1>Plot calibration graphs from univariate linear models</h1>
    </div>

    
    <p>Produce graphics of calibration data, the fitted model as well
  as confidence, and, for unweighted regression, prediction bands.</p>
    

    <pre><span class='fu'>calplot</span>(<span class='no'>object</span>, <span class='kw'>xlim</span> <span class='kw'>=</span> <span class='fu'>c</span>(<span class='st'>"auto"</span>, <span class='st'>"auto"</span>), <span class='kw'>ylim</span> <span class='kw'>=</span> <span class='fu'>c</span>(<span class='st'>"auto"</span>, <span class='st'>"auto"</span>),
    <span class='kw'>xlab</span> <span class='kw'>=</span> <span class='st'>"Concentration"</span>, <span class='kw'>ylab</span> <span class='kw'>=</span> <span class='st'>"Response"</span>, <span class='kw'>alpha</span><span class='kw'>=</span><span class='fl'>0.05</span>, <span class='kw'>varfunc</span> <span class='kw'>=</span> <span class='kw'>NULL</span>)</pre>
    
    <h2 class="hasAnchor" id="arguments"><a class="anchor" href="#arguments"></a> Arguments</h2>
    <dl class="dl-horizontal">
      <dt>object</dt>
      <dd>
    A univariate model object of class <code>lm</code> or 
    <code><a href='http://www.rdocumentation.org/packages/MASS/topics/rlm'>rlm</a></code> 
    with model formula <code>y ~ x</code> or <code>y ~ x - 1</code>.
  </dd>
      <dt>xlim</dt>
      <dd>
    The limits of the plot on the x axis.
  </dd>
      <dt>ylim</dt>
      <dd>
    The limits of the plot on the y axis.
  </dd>
      <dt>xlab</dt>
      <dd>
    The label of the x axis.
  </dd>
      <dt>ylab</dt>
      <dd>
    The label of the y axis.
  </dd>
      <dt>alpha</dt>
      <dd>
    The error tolerance level for the confidence and prediction bands. Note that this 
    includes both tails of the Gaussian distribution, unlike the alpha and beta parameters
    used in <code><a href='lod.html'>lod</a></code> (see note below).
  </dd>
      <dt>varfunc</dt>
      <dd>
    The variance function for generating the weights in the model.
    Currently, this argument is ignored (see note below).
  </dd>
    </dl>
    
    <h2 class="hasAnchor" id="value"><a class="anchor" href="#value"></a>Value</h2>

    <p>A plot of the calibration data, of your fitted model as well as lines showing
  the confidence limits. Prediction limits are only shown for models from
  unweighted regression.</p>
    
    <h2 class="hasAnchor" id="note"><a class="anchor" href="#note"></a>Note</h2>

    <p>Prediction bands for models from weighted linear regression require weights
  for the data, for which responses should be predicted. Prediction intervals
  using weights e.g. from a variance function are currently not supported by
  the internally used function <code>predict.lm</code>, therefore,
  <code>calplot</code> does not draw prediction bands for such models.</p>
    <p>It is possible to compare the <code>calplot</code> prediction bands with the
  <code><a href='lod.html'>lod</a></code> values if the <code>lod()</code> alpha and beta parameters are
  half the value of the <code>calplot()</code> alpha parameter.</p>
    

    <h2 class="hasAnchor" id="examples"><a class="anchor" href="#examples"></a>Examples</h2>
    <pre class="examples"><div class='input'><span class='fu'>data</span>(<span class='no'>massart97ex3</span>)
<span class='no'>m</span> <span class='kw'>&lt;-</span> <span class='fu'>lm</span>(<span class='no'>y</span> ~ <span class='no'>x</span>, <span class='kw'>data</span> <span class='kw'>=</span> <span class='no'>massart97ex3</span>)
<span class='fu'>calplot</span>(<span class='no'>m</span>)</div><img src='calplot-2.png' alt='' width='540' height='400' /></pre>
  </div>
  <div class="col-md-3 hidden-xs hidden-sm" id="sidebar">
    <h2>Contents</h2>
    <ul class="nav nav-pills nav-stacked">
      <li><a href="#arguments">Arguments</a></li>
      
      <li><a href="#value">Value</a></li>

      <li><a href="#note">Note</a></li>
      
      <li><a href="#examples">Examples</a></li>
    </ul>

    <h2>Author</h2>
    
  Johannes Ranke 
  <a href='mailto:jranke@uni-bremen.de'>jranke@uni-bremen.de</a> 
  <a href = 'http://www.uft.uni-bremen.de/chemie/ranke'>http://www.uft.uni-bremen.de/chemie/ranke</a>

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