<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">I retract my question. <div>Ben suggested that I try some numbers and compare them to what I would expect.<div>I see that this gamma takes the quantile, and shape parameter and always has has a rate=1 or scale=1. </div><div><br></div><div>To get the value at the z quantile of a gamma with shape=k, scale=theta or rate=1/theta I can use</div><div>theta*inv_cumd_gamma(z,k)</div><div><br></div><div>Maybe this will save the next person a little time.</div><div>-Mollie<br><div><div apple-content-edited="true"><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div><span class="Apple-style-span" style="font-size: 12px; "><div><br></div></span></div></div> </div><br><div><div>On 18-Jan-11, at 8:24 PM, Mollie Brooks wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div>Hi,<br>I'm guessing Hans is the best person to ask, but I thought this could benefit others as well.<br><br>I'm having trouble relating inv_cumd_gamma() to the gamma distribution I know which has 2 parameters. I've seen the example at<br><a href="http://otter-rsch.com/admbre/examples/gamma/gamma.html">http://otter-rsch.com/admbre/examples/gamma/gamma.html</a><br>which uses it as follows:<br> theta*inv_cumd_gamma(z, 1/theta)<br><br>If z is an observation of the cumulative density, and inv_cumd_gamma should map z back to the gamma distribution, then I'm wondering why the gamma distribution only has one parameter. Do I need to do another transformation to get k in there?<br><br>thanks,<br>Mollie<br><br><br>_______________________________________________<br>Users mailing list<br>Users@admb-project.org<br>http://lists.admb-project.org/mailman/listinfo/users<br><br></div></blockquote></div><br></div></div></div></body></html>