Re: st: A strange data problem

[Ted Anagnoson <anag999@silcom.com>]

Hi Maoyong,

It is probably the storage type - you have very large numbers (3.76e+10), 
the variable stored as float has only 8 sig digits (I think) while the 
double has twice that.  I could see that resulting in a difference on these 
large numbers of 145 or so....

Check the manual for storage types - I think that is where I would start

Ted Anagnoson
Political Science
Cal State LA



At 10:15 PM 1/15/05 -0800, you wrote:

> Dear Stata User,
>
>         I met a strange problem in dealing with my scanner data.  I use 
> stata transfer to transger the original data to dta files.  One of my 
> variables is UPC whose storage type is double.  I found that when I 
> generate a new variable equal to UPC, the new variable is totally 
> different from UPC.
>
> Like this:
> gen UPC1 = UPC
> gen diff = UPC1 - UPC
> sum
> des
>
>     Variable |       Obs        Mean    Std. Dev.       Min        Max
> -------------+--------------------------------------------------------
>          UPC |   1780770    3.76e+10    1.96e+11   1.00e+10   2.72e+12
>         UPC1 |   1780770    3.76e+10    1.96e+11   1.00e+10   2.72e+12
>         diff |   1780770    144.9445    4290.722    -105114     116086
>
> . des
>
> Contains data from D:\temp\dairyHH1.dta
>   obs:     1,780,770
>  vars:             3                          18 Jun 2003 13:27
>  size:    35,615,400 (66.0% of memory free)
> -------------------------------------------------------------------------------
>               storage  display     value
> variable name   type   format      label      variable label
> -------------------------------------------------------------------------------
> UPC             double %15.0g                 UPC -
>                                                 system/generation/vendor/item
> UPC1            float  %9.0g
> diff            float  %9.0g
> -------------------------------------------------------------------------------
> Sorted by:
>      Note:  dataset has changed since last saved
>
> Anyone know what's wrong with this?
>
> Warm regards,
>
> Maoyong Fan
>
>
>
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