Cumulative Insect-Days

[#1]

Hello,

I need help calculating something called Cumulative Insect-Days per treatment. I don't know how to do that as it involves calculating the mean of specific rows and the difference between two specific rows.

Cumulative insect-days = [ (Xi + Xi+1) * average(Y+Yi+1) ] + (Yi+1)

Xi and Xi+1 are adjacent points in time

Yi and Yi+1 are corresponding insect numbers

I have done these calculations in Excel (attached), but I need to do them in JMP as I have several columns and rows of data. Formula is in excel.

Thank you,

Bordini

[#2 · Accepted solution]

Here is the formula that will create the values you want

If( Row() == 1,
	val = :"Cumulative insect-days"n;
	lastVal = val;
,
	val = Mean( :Number of Insects, Lag( :Number of Insects ) ) * (:Date of Year - Lag( :Date of Year )) + lastVal;
	lastVal = val;
);
val;

[#3]

This approach works nicely. Thank you very much. I appreciate your help.