title: How to make a normally distributed variable depend on entries and time in R?
body: <p>I'm trying to generate a dataset of cross sectional time series to estimate uses of different models.
  In this dataset, I have a ID variable and time variable. I'm trying to add a normally distributed variable that depends on the two identifications. In other words, how do I create a variable that recongizes both ID and time in R?
  If my question appears uncertain, feel free to ask any questions.
  Thanks in advance.</p>
  <pre><code>df2 &lt;- read.table(
  text =
  &quot;Year,ID,H,
  1,1,N(2.3),
  2,1,N(2.3),
  3,1,N(2.3),
  1,2,N(0.1),
  2,2,N(0.1),
  3,2,N(0.1),
  &quot;, sep = &quot;,&quot;, header = TRUE)
  </code></pre>