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list manipulation - Filtering and Replacing outliers


I have a set of data that measurements of temperature vs time (date). It is easy to realize when the sensor went wrong as one might see a blip on the data. How to teach to Mathematica to: 1) Detect the "Blip" 2) Delete this Blip 3) Replace the corrupted point for one derived as the mean of the previous data (before the corrupted one) and the one after (after the corrupted one). Thanks in advance !!!


I have tried to setup a test in which each pair of data were compared and if the difference between them was greater than 3 C (or 5C depending how rigorous you want to be). But my reasoning did not work properly.



Thanks in Advance


Ed


The dataset is:


l = {{"2013-11-20 23:00:00", 23.52}, {"2013-11-21 00:00:00", 
  23.55}, {"2013-11-21 01:00:00", 23.62}, {"2013-11-21 02:00:00", 
  23.61}, {"2013-11-21 03:00:00", 23.53}, {"2013-11-21 04:00:00", 
  23.45}, {"2013-11-21 05:00:00", 23.52}, {"2013-11-21 06:00:00", 
  23.4}, {"2013-11-21 07:00:00", 24.02}, {"2013-11-21 08:00:00", 
  26.7}, {"2013-11-21 09:00:00", 27.54}, {"2013-11-21 10:00:00", 
  29.67}, {"2013-11-21 11:00:00", 28.3}, {"2013-11-21 12:00:00", 

  17.94}, {"2013-11-21 13:00:00", 27.42}, {"2013-11-21 14:00:00", 
  25.82}, {"2013-11-21 15:00:00", 24.61}, {"2013-11-21 16:00:00", 
  23.91}, {"2013-11-21 17:00:00", 24.58}, {"2013-11-21 18:00:00", 
  24.31}, {"2013-11-21 19:00:00", 23.18}, {"2013-11-21 20:00:00", 
  28.99}, {"2013-11-21 21:00:00", 22.56}, {"2013-11-21 22:00:00", 
  22.01}}

TempPlot




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