Grouped observations in a data set of clinic records

Data on patients from clinic visit records

• PATIENT= patient identifier
• VISIT= visit number
• observations have been sorted by PATIENT VISIT
• each observation is a visit to the clinic

PATIENT   VISIT    MONTH    DAY   YEAR    WEIGHT    SYSTOLIC    DIASTOLC

20147       1       11      13    1995      187        126          78
20147       2       11      20    1995      189        142          77
20147       3       11      22    1995      188        129          71
20147       4       11      27    1995      190        126          61
20147       5       12      11    1995      192        140          65
20147       6        1       4    1996      194        141          65
20147       7        1      25    1996      202        132          65
20147       8        1      30    1996      200        124          70
20147       9        3       8    1996      201        137          67
20147      10        4       4    1996      202        132          69
20147      11        5       3    1996      212        132          69
20147      12        5      10    1996      218        131          76
20147      13        5      21    1996      222        147          84

20158       1       10      30    1995      118        124          64
20158       2       11      13    1995      997        997         997
20158       3        1       2    1996      127        112          70
20158       4        1      30    1996      132        104          50
20158       5        2      27    1996      138        110          70
20158       6        3      19    1996      142        110          66
20158       7        4       9    1996      145        120          70
20158       8        4      16    1996      145        122          70
20158       9        4      24    1996      997        997         997
20158      10        5      13    1996      150        110          70

20166       1       11       7    1995      179        110          80
20166       2       11      27    1995      997        997         997
20166       3       12      27    1995      176        108          70
20166       4        1      29    1996      180        110          68
20166       5        2      28    1996      183        100          70
20166       6        3      29    1996      187        110          70
20166       7        4      12    1996      189        100          50
20166       8        4      26    1996      189        114          64
20166       9        5      10    1996      191        100          64
20166      10        5      24    1996      192        100          70
20166      11        5      31    1996      192        100          60

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