AW: Area under Curve
- To: mathgroup at smc.vnet.net
- Subject: [mg7963] AW: [mg7943] Area under Curve
- From: Buttgereit <Buttgereit at compuserve.com>
- Date: Wed, 30 Jul 1997 02:37:26 -0400
- Sender: owner-wri-mathgroup at wolfram.com
Hi Sankar, you can use ListIntegrate to get your AUC. As well you could use an InterpolatingFunction object and then use NIntegrate. Note that the result depends on the way of interpolation. Using first ord= er interpolation (straight lines between adjacent points) you would have to calculate the sum of the areas of n-1 trapezoids (what is trivial). If you should like to connect your points using a function like a stair-case, your problem reduces to calculating the mean of your yi and multiply it with your x-range (if equally spaced). You could also fit a suitable model to your data first and then use Integrate on your model. "The Mathematica Journal" Volume 7, Issue 1 (Winter 1997) pp. 29 gives an= example of this and shows how to estimate the error of the calculated AUC= (given in the "In and Out" section - you might already get it on MathSource). Greetings, Peter ---------- Von: Sankar Baruah[:] Gesendet: Freitag, 25. Juli 1997 11:05 An: INTERNET:mathgroup at smc.vnet.net Betreff: [mg7943] Area under Curve by dub-img-4.compuserve.com (8.8.6/8.8.6/2.2) with SMTP id FAA21723; Fri, 25 Jul 1997 05:05:31 -0400 (EDT) id CAA09090; Fri, 25 Jul 1997 02:40:21 -0400 id CAA09084; Fri, 25 Jul 1997 02:40:20 -0400 From: Sankar Baruah <sankar-baruah at uiowa.edu> To: mathgroup at smc.vnet.net Subject: [mg7963] [mg7943] Area under Curve Organization: The University of Iowa I am new to Mathematica and would really appreciate some pointers from experienced users. I have a 2 variable data set of about 50 observations. I want to plot each obseravtion and calculate the area under the curve. How do I do this in Mathematica ? Are there examples in the Mathematica Book and/or are there separate application notes etc. available ? Thanks. Sankar.