title: Plot survival and hazard function of survreg using curve()
body: <p>I have the following survreg model: </p>
  
  <pre><code>Call:
  survreg(formula = Surv(time = (ev.time), event = ev) ~ age, 
      data = my.data, dist = "weib")
               Value Std. Error    z        p
  (Intercept) 4.0961     0.5566 7.36 1.86e-13
  age         0.0388     0.0133 2.91 3.60e-03
  Log(scale)  0.1421     0.1208 1.18 2.39e-01
  Scale= 1.15 
  
  Weibull distribution
  </code></pre>
  
  <p>I would like to plot the <strong>hazard</strong> function and the <strong>survival</strong> function based on the above estimates.<br>
  I don't want to use <code>predict()</code> or <code>pweibull()</code> (as presented here <a href="http://www.unc.edu/courses/2010spring/ecol/562/001/docs/lectures/lecture24.htm" rel="noreferrer">Parametric Survival</a> or here <a href="https://stackoverflow.com/questions/9151591/how-to-plot-the-survival-curve-generated-by-survreg-package-survival-of-r">SO question</a>.  </p>
  
  <p>I would like to use the <code>curve()</code> function. Any ideas how I can accomplish this? It seems the Weibull function of the survreg uses other definitions of scale and shape than the usual (and different that for example rweibull).</p>
  
  <p><strong>UPDATE:</strong> I guess what I really require it to express hazard / survival as a function of the estimates <code>Intercept</code>, <code>age (+ other potential covariates)</code>, <code>Scale</code> without using any ready made <code>*weilbull</code> function. </p>