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.