Area under lethality curve

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   If you are interested in this topic you might find the post at http://dairyscience.info/forum/topic260_post1109.html#1109 of some interest- comparison of Fo values obtained using 3 numerical integration methods (trapezoidal, Simpson's and Romberg rules)
 and 7 data sets.

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Admin Members Profile Send Private Message Find Members Posts Add to Buddy List Admin Group Administrator Joined: 01 Sep 2009 Location: N. Ireland Status: Offline Points: 390	Post Options Post Reply Quote Admin Report Post Thanks(0) Quote Reply Topic: Area under lethality curve Posted: 07 Apr 2011 at 11:23pm
	If you are interested in this topic you might find the post at http://dairyscience.info/forum/topic260_post1109.html#1109 of some interest- comparison of Fo values obtained using 3 numerical integration methods (trapezoidal, Simpson's and Romberg rules) and 7 data sets.

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Admin Members Profile Send Private Message Find Members Posts Add to Buddy List Admin Group Administrator Joined: 01 Sep 2009 Location: N. Ireland Status: Offline Points: 390	Post Options Post Reply Quote Admin Report Post Thanks(0) Quote Reply Posted: 02 Dec 2010 at 11:45pm
	This topic is well-described in older textbooks e.g. counting "squares" under the curve and dividing this number by the number of squares in the rectangle obtained by plotting a lethality value of 1 for 1 minute. Similarly a planimiter can be used to obtain the area under the curve which is divided by the area (determined using the planimiter) of the the rectangle obtained by plotting a lethality value of 1 for 1 minute. It is also possible to cut out the areas, weight them and to divide the weight of the smaller area into the weight of the larger one to obtain the F value at the reference temperature. However, it is very easy to do this calculation using a spreadsheet and numerical integration. I will say a little more about this when I get some more time. Additional material added 3-12-2010 Area can be calculated using the trapezoidal rule (also known as the trapezoid rule) or Simpson's rule. The free F calculator on this site uses the trapezoidal rule to calculate area under lethality time curve. You can also download a spreadsheet to do the calculation. Another option is to use Excel to calculate the trend line, the equation (use the polynomial option, order 2) for the curve and the r-value. If the r value is >0.9 you could consider integrating the equation if your knowledge of calculus is good. WolframAlpha can be used to check your calculation.

mstrange Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 30 Nov 2010 Status: Offline Points: 4	Post Options Post Reply Quote mstrange Report Post Thanks(0) Quote Reply Posted: 01 Dec 2010 at 11:24pm
	Hi we are interested in knowing more about ways of getting area undr lethal rate curve. Any help appreciated.