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From |
"Michael W. Beets" <beetsm@onid.orst.edu> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
st: Collpasing Data by every 4 observations |

Date |
Wed, 21 May 2008 12:03:50 -0700 |

I have 15sec interval data collected on individuals over the course of a single day.

The data look like the following, where "counts" are the primary outcome and time is the "time" (fraction of 24hrs) the counts occurred.

What I am attempting to do is create a mean of every 4 15sec intervals to reflect the average counts/min. Hence, if a person is monitored (at 15sec intervals) over the duration of 1hr, they would have 240 lines of data containing counts. This needs to be collapsed into average counts/min (resulting in 60 lines of data/person).

However, I am unaware of how to specify the collapse command to take the average of every 4 lines of data.

. list counts time in 1/20

+------------------+

| counts time |

|------------------|

1. | 210 .333507 |

2. | 75 .333681 |

3. | 166 .333854 |

4. | 466 .334028 |

5. | 29 .334201 |

|------------------|

6. | 19 .334375 |

7. | 12 .334549 |

8. | 0 .334722 |

9. | 0 .334896 |

10. | 16 .335069 |

|------------------|

11. | 0 .335243 |

12. | 398 .335417 |

13. | 566 .33559 |

14. | 0 .335764 |

15. | 10 .335938 |

|------------------|

16. | 1133 .336111 |

17. | 651 .336285 |

18. | 139 .336458 |

19. | 393 .336632 |

20. | 430 .336806 |

+------------------+

r; t=0.03 12:03:12

Michael W. Beets, M.P.H., Ph.D.

Department of Public Health

Oregon State University

256 Waldo Hall

Corvallis, OR 97331-6406

PH: 541-738-2888

CELL: 541-231-6673

FAX: 541-737-4001

Email: beetsm@onid.orst.edu

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**Follow-Ups**:**Re: st: Collpasing Data by every 4 observations***From:*"Scott Merryman" <scott.merryman@gmail.com>

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