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

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

Subject |
RE: st: Testing for a contiguous subset of observations? |

Date |
Fri, 30 Nov 2007 12:01:59 -0000 |

This lumps together all the zeros for each -id- regardless of when they occurred. That is valid if there is at most one spell of zeros for each -id-. Otherwise I don't think it matches the problem. Nick n.j.cox@durham.ac.uk Maarten buis bys id (observation) : gen zero = Activity == 0 bys id zero (observation) : gen nzero = _N if zero == 0 replace nzero = 0 if nzero == . gen activity2 = activity if nzero < 60 & nzero --- BW Wheeler <ben.wheeler@bristol.ac.uk> wrote: > I'm having trouble figuring out a solution to this data management > problem, and have exhausted all books and findit (partly as it's hard > to know what to search for)! > > I have time series data captured from accelerometers, with an > observation of 'activity counts' logged every 10 seconds for several > days for each individual. If the number of counts is zero continuously > for any period of 10 minutes or more (i.e. 60+ observations), we need > to assume that the accelerometer was not being worn, and to treat > these zeros as missing. > > So, my data look something like this: > > Observation Date Time Activity > 1 13/05/2006 15:20:00 230 > 2 13/05/2006 15:20:10 215 > 3 13/05/2006 15:20:20 0 > 4 13/05/2006 15:20:30 0 > 5 13/05/2006 15:20:40 0 > ... > > Does anyone have any ideas of how I can replace the 'Activity' value > with missing, if that value is a zero in the midst of a continuous > series of 60+ zeros? * * For searches and help try: * http://www.stata.com/support/faqs/res/findit.html * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/

**Follow-Ups**:**RE: st: Testing for a contiguous subset of observations?***From:*BW Wheeler <ben.wheeler@bristol.ac.uk>

**References**:**st: Testing for a contiguous subset of observations?***From:*BW Wheeler <ben.wheeler@bristol.ac.uk>

**Re: st: Testing for a contiguous subset of observations?***From:*Maarten buis <maartenbuis@yahoo.co.uk>

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