how to use jsl to calculate standard deviation by ID
Hi, I have a table similar to this, and I wanted to select IDs where there are more than one entry and calculate standard deviation of the result grouped by ID. For example, in this case, I need to select ID 12345 and calculate standard deviation of the first 3 results. I know I can do this by tabulate, but my actual table is very big, more than 1 million rows, tabulate by ID and calculate standa...