noob Q: how can I perform a calculation w/ values from different rows?

[tomato]

I am just beginning to use JMP scripting so please forgive if this seems very elementary . . .

I have a data table full of values for Assay and Total Impurity of a drug substance on stability.

data looks like this:

Lot# / Condition / Component / Time (Months) / Test Result
ABC123 / 25 °C / 60 %RH / Total Impurities / 00 / 0.45
ABC123 / 25 °C / 60 %RH / Assay / 00 / 98.00
ABC123 / 25 °C / 60 %RH / Total Impurities / 03 / 0.43
ABC123 / 25 °C / 60 %RH / Assay / 03 / 100.00
DEF456 / 25 °C / 60 %RH / Total Impurities / 00 / 0.45
DEF456 / 25 °C / 60 %RH / Assay / 00 / 98.00
DEF456 / 25 °C / 60 %RH / Total Impurities / 03 / 0.43
DEF456 / 25 °C / 60 %RH / Assay / 03 / 100.00

I would like to add a new column for difference in assay value from T0 (00 Months) to current Time.

So the Test Result of this row, minus the Test Result in the row that has the same Lot number as this row and the same values for Component and Condition, with a value of 00 for Time (Months)

So for the 4th row down it would be 100 - 98, which would give a value of +2

Is that possible?

[Cynthia_sas]

Hi:
There's a separate forum for JMP users:
http://support.sas.com/forums/forum.jspa?forumID=43

And the folks who use JMP and JSL (JMP Scripting Language) are mostly monitoring that forum. That would be the best place to post your question.

cynthia