# st: RE: Re: sum across observations until a certain cutpoint

 From "Nick Cox" To Subject st: RE: Re: sum across observations until a certain cutpoint Date Sun, 9 Nov 2008 17:59:13 -0000

```Still not very clear to me, but I guess something like this

20      10    20    5       10
5       10    15    30      2
100     2      3    3       4

So that the three individuals above had completed 4, 4, 0 tasks in the
first 60 seconds.

How many within 60 seconds?

gen cumul = 0
gen within60 = 0

qui forval i = 1/5 {
replace cumul = cumul + task`i'
replace within60 = `i' if cumul <= 60
}

Nick
n.j.cox@durham.ac.uk

Amanda Botticello PhD, MPH

IT's a "wide" dataset...subjects completed up to 200 items in a task,
and we recorded the number of seconds it took to complete each item.  I
can create a sum of the total number of items completed and total time;
now I want to find out how many items each individual completed in 60,
90, and 120 seconds.  Does that help?

>>> "Martin Weiss" <martin.weiss1@gmx.de> 11/9/2008 11:00 AM >>>

Well, if you want the running sum, look at -help sum()-. But maybe you
could
give us a peek at your data structure, that would assist in answering
question...

"Amanda Botticello" <abotticello@kmrrec.org>

>I have a dataset of test items and the time (in seconds)to complete
each
>item.  I need to create a variable that sums the time variables up to a

>certain number -- i.e., 60, 90, 120 seconds.  Is there a way I can use
the
>egen newvar = rowtot (time*) command to count up to 60 seconds, etc?

*
*   For searches and help try:
*   http://www.stata.com/help.cgi?search
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/
```