title: Creating tables in markdown using knitr: formatting issues
body: <p>I keep running in to problems about formatting tables in markdown like the following: why is the following table align to the right but the table after is align to the center?</p>
  
  <pre><code>```{r}
  dep.vars  &lt;-  letters[1:4]
  table.3   &lt;-  1:4
  ```
  **Table 3: Box-Cox estimates for transformation parameter $\lambda$**  
  
  | Dep. variable      | $\hat{\lambda}$ |  
  |  -----------:           | :-------------: |  
  | `r dep.vars[1]`         | `r table.3[1]`  |  
  | `r dep.vars[2]`         | `r table.3[2]`  |  
  | `r dep.vars[3]`         | `r table.3[3]`  |    
  | `r dep.vars[4]`         | `r table.3[4]`  |  
  
  
  
  | Hi there      | Everybody |  
  |  -----------:           | :-------------: |  
  | `r dep.vars[1]`         | $\alpha$  |  
  </code></pre>
  
  <p>I am knitting in to HTML.</p>
  
  <p>I would appreciate some pointers to documentation that addresses issues like this in further detail than the markdown quick reference.</p>