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From |
"Nick Cox" <n.j.cox@durham.ac.uk> |

To |
<statalist@hsphsun2.harvard.edu> |

Subject |
st: RE: RE: RE: Re: sum across observations until a certaincutpoint |

Date |
Sun, 9 Nov 2008 18:28:33 -0000 |

Not so. If you can analyse the data, you can also restructure them! Sorry, but your answer is still ambiguous to me as you didn't answer my question. I offered a choice of two wordings. You wrote your own. This may be what you want: Say items go -item1- to -item200-. gen within60 = 0 qui forval i = 1/200 { replace within60 = within60 + 1 if time`i' > 0 & time`i' <= 60 } Nick n.j.cox@durham.ac.uk Amanda Botticello I want to calculate how many items each subject completed within 60 seconds. And I can't do anything about the data structure, unfortunately. >>> "Nick Cox" <n.j.cox@durham.ac.uk> 11/9/2008 1:14 PM >>> You've lost me. I don't understand how your data structure copes with time spent on failed tasks. Please be clear: Do you want to cumulate times and see how many tasks in total were completed within a total of 60 seconds, as implied by your original question, or do you just want to count how many tasks were individually completed within 60 seconds? Incidentally, I think you would be better off reshaping this to long. Nick n.j.cox@durham.ac.uk Amanda Botticello The data is more like this: id item1 time1 item2 time2 itmem3 time3 1 1 2 1 3 1 2 2 1 5 0 0 0 0 3 1 3 1 3 1 5 The variable "item" is coded 0,1, where 1 indicates the item was completed Time is recorded in number of seconds to complete. If they didn't complete an item, the time is 0 >>> "Nick Cox" <n.j.cox@durham.ac.uk> 11/9/2008 12:59 PM >>> Still not very clear to me, but I guess something like this task1 task2 task3 task4 task5 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 your 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/

**References**:**st: sum across observations until a certain cutpoint***From:*"Amanda Botticello" <abotticello@kmrrec.org>

**st: Re: sum across observations until a certain cutpoint***From:*"Martin Weiss" <martin.weiss1@gmx.de>

**st: Re: sum across observations until a certain cutpoint***From:*"Amanda Botticello" <abotticello@kmrrec.org>

**st: RE: Re: sum across observations until a certain cutpoint***From:*"Nick Cox" <n.j.cox@durham.ac.uk>

**st: RE: Re: sum across observations until a certain cutpoint***From:*"Amanda Botticello" <abotticello@kmrrec.org>

**st: RE: RE: Re: sum across observations until a certain cutpoint***From:*"Nick Cox" <n.j.cox@durham.ac.uk>

**st: RE: RE: Re: sum across observations until a certain cutpoint***From:*"Amanda Botticello" <abotticello@kmrrec.org>

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