how to get cumulative sum data?

[#1]

How do I use JMP9 to get cumulative sum data?  That is, I want to accumulate data from column COUNT in a new column called SUM,

COUNT      SUM

0                0

0                0

1                1

1                2

0                2

Thank you for your help!!

[#2 · Accepted solution]

Use the Column Formula and enter the above expression using the Statistical>Summation, Row and Column of interest with subscript i

[#3]

Hi

I have difficulty to understand at the attached formula. Could you please explain what calculation is done by using this formula with an example? 

[#4]

The formula specification for JMP 13.2.1 is:

Col Cumulative Sum( :weight )