<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html><head><title>R: Visits to Lake Somerville</title>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<link rel="stylesheet" type="text/css" href="R.css">
</head><body>

<table width="100%" summary="page for Somerville"><tr><td>Somerville</td><td align="right">R Documentation</td></tr></table>

<h2>Visits to Lake Somerville </h2>

<h3>Description</h3>


<p>a cross-section from 1980
</p>
<p><EM>number of observations</EM> :  659
</p>
<p><EM>observation</EM> :  individuals
</p>
<p><EM>country</EM> :  United States
</p>


<h3>Usage</h3>

<pre>data(Somerville)</pre>


<h3>Format</h3>

<p>A dataframe containing :
</p>

<dl>
<dt>visits</dt><dd><p>annual number of visits to lake Somerville</p>
</dd>
<dt>quality</dt><dd><p>quality ranking score for lake Somerville</p>
</dd>
<dt>ski</dt><dd><p>engaged in water&ndash;skiing at the lake ?</p>
</dd>
<dt>income</dt><dd><p>annual household income</p>
</dd>
<dt>feeSom</dt><dd><p>annual user fee paid at lake Somerville ?</p>
</dd>
<dt>costCon</dt><dd><p>expenditures when visiting lake Conroe</p>
</dd>
<dt>costSom</dt><dd><p>expenditures when visiting lake Somerville</p>
</dd>
<dt>costHoust</dt><dd><p>expenditures when visiting lake Houston</p>
</dd>
</dl>



<h3>Source</h3>


<p>Seller, Christine,  John R.   Stoll and  Jean&ndash;Paul  Chavas (1985) &ldquo;Valuation of empirical measures of welfare change : a comparison of nonmarket techniques&rdquo;, <EM>Land Economics</EM>, <B>61(2)</B>, may, 156&ndash;175.
</p>
<p>Gurmu, Shiferaw  and  Pravin K.  Trivedi (1996) &ldquo; Excess zeros in count models for recreational trips&rdquo;, <EM>Journal of Business and Economics Statistics</EM>, <B>14(4)</B>, october, 469&ndash;477.
</p>
<p>Santos Silva, Jao M. C. (2001) &ldquo;A score test for non&ndash;nested hypotheses with applications to discrete data models&rdquo;, <EM>Journal of Applied Econometrics</EM>, <B>16(5)</B>, 577&ndash;597.
</p>


<h3>References</h3>


<p>Journal of Business Economics and Statistics web site : <a href="http://www.amstat.org/publications/jbes/">http://www.amstat.org/publications/jbes/</a>.
Cameron, A.C.  and   Trivedi P.K. (1998) <EM>Regression analysis of count data</EM>, Cambridge University Press, <a href="http://cameron.econ.ucdavis.edu/racd/racddata.html">http://cameron.econ.ucdavis.edu/racd/racddata.html</a>, chapter 6.
</p>


<h3>See Also</h3>

<p><code>Index.Source</code>, <code>Index.Economics</code>, <code>Index.Econometrics</code>, <code>Index.Observations</code></p>


</body></html>
