title: dplyr with stats test
body: <p>I have the follow data setup</p>
  
  <pre><code>library(dplyr)
  library(broom)
  
  pop.mean = 0.10
  
  df = data.frame( 
    trial    = as.integer(runif(1000, min = 5, max = 20)),
    success  = as.integer(runif(1000, min = 0, max = 20)),
    my.group = factor(rep(c("a","b","c","d"), each = 250))
  )
  </code></pre>
  
  <p>I want to group on my.group and apply binom.test</p>
  
  <pre><code>bi.test &lt;- df %&gt;% group_by(my.group) %&gt;%
    do(test = binom.test(sum(success),
                         sum(trial),
                         pop.mean,
                         alternative = c("two.sided"),
                         conf.level = 0.95))
  </code></pre>
  
  <p>Getting error message, cannot find success what am I doing wrong here? </p>