title: How to use dplyr to generate a frequency table
body: <p>I like to create a table that has the frequency of several columns in my data frame. I am copying part of my data frame below. </p>
  
  <p>The table is supposed to have frequency (both n and %) of "red" in Color and "F" in Gender. </p>
  
  <p>I think that the dplyr package could do this but I cannot figure it out. </p>
  
  <p>Thank you-</p>
  
  <pre>
      RespondentID    Color        Gender   
  1     1503          Red           F      
  2     1653          NA            M   
  3     1982          Red           F   
  4     4862          Red           NA   
  15    4880          Blue          M  
  
  </pre>