title: quantile & aggregate on zoo object in R
body: <p>I have a <code>zoo</code> object looking like </p>
  
  <pre><code>library(zoo)
  library(lubridate)
  TimeStamp=seq(dmy("01/01/2002"), dmy("17/12/2014"), by="day")
  Dummy= rnorm(length(TimeStamp))
  Temp=zoo(Dummy,TimeStamp)
  </code></pre>
  
  <p>I am trying to calculate the 5%, 33%, 67% and 95% percentile/quantile for each day in a year to create a "norm".
  So for the 01/01 I would like to have the 4 quantiles values based on all the observation I have for the 1st of Jan in my Dataset. Same thing for every day.</p>
  
  <p>Right now I am using that:</p>
  
  <pre><code>aggregate(Temp ~ day(index(Temp)) + month(index(Temp)), FUN = 'quantile')
  </code></pre>
  
  <p>The problem is that using this function I am not sure of what value return the <code>quantile</code> function.</p>
  
  <p>Any suggestion ?</p>