title: Line graph from replicate data with error bars
body: <p>Im trying to make a growth curve with 2 variables on the same plot (Media1 and Media2). I have 3 time points (T1,T2...) and each time point was repeated 3 times (R1,R2,R3). I need to average the replicates and make a line graph with error bars. Example of the data:</p>
  <pre><code>Time Replicate      Media1     Media2
  1       T0        R1 0.013733333 0.03770000
  2       T0        R2 0.008233333 0.03690000
  3       T0        R3 0.013333333 0.03760000
  4       T1        R1 0.018166667 0.03680000
  5       T1        R2 0.013466667 0.03570000
  6       T1        R3 0.018366667 0.03700000
  7       T2        R1 0.028066667 0.04420000
  8       T2        R2 0.022966667 0.04400000
  9       T2        R3 0.027866667 0.04420000
  10      T3        R1 0.041333333 0.05536667
  11      T3        R2 0.033433333 0.05476667
  12      T3        R3 0.039833333 0.05446667
  </code></pre>
  <p>I have figured out how to average the replicates using this:</p>
  <pre><code>.colMeans(df$Media1, 3, length(df$Media1) / 3)
  </code></pre>
  <p>And I know how to plot it in ggplot. I just can't figure out how to get error bars on the line graph from the original non-averaged data.</p>
  <p>Thanks for any help</p>