Date:         Mon, 14 Oct 2002 12:39:41 -0500
Reply-To:     Carol Albright <calbright@VISI.COM>
Sender:       "SPSSX(r) Discussion" <SPSSX-L@LISTSERV.UGA.EDU>
From:         Carol Albright <calbright@VISI.COM>
Subject:      Re: log transform
Comments: To: pasherman@WORLDNET.ATT.NET
In-Reply-To:  <04C708E60B4CD31198440008C7A447ED0AFB88F0@mail.chkd.org>
Content-Type: text/plain; charset="iso-8859-1"

Hi, Pat & all,

        Does your original data include 0 as a valid value?  If so, then include +
1 in your formula or the resulting LN-transformed data will be missing:


compute ln_old = ln(olddata).
compute ln_old1 = ln(olddata + 1).
exe.
list all.

List

>Warning # 602
>The argument for the natural log function is less than or equal to zero.
>The result has been set to the system-missing value.

>Command line: 5  Current case: 1  Current splitfile group: 1



 OLDDATA   LN_OLD  LN_OLD1

     .00      .        .00
    1.00      .00      .69
    2.00      .69     1.10
    3.00     1.10     1.39
    4.00     1.39     1.61
    5.00     1.61     1.79


At 11:39 AM 10/14/02 -0400, Paulson, James wrote:
>Use the Compute platform and enter:
>
>        LN(Oldvariablename)
>
>This will allow you to create a new variable that contains natural log
>transformations of your old skewed data.
>
>Good luck!
>James Paulson
>
>> -----Original Message-----
>> From: Patricia Sherman [mailto:pasherman@WORLDNET.ATT.NET]
>> Sent: Monday, October 14, 2002 1:49 AM
>> To: SPSSX-L@LISTSERV.UGA.EDU
>> Subject: log transform
>>
>> I have very skewed data and need to perform either a log transform (LN)
>> or a negative inverse transformation.  Can anyone advise me as to how to
>> go about carrying out these operations?  I have SPSS 11.0
>>
>>
>>
>> Thank you very much.
>>
>>
>>
>> Pat Sherman
>>
>>
>>
>> ____________________________________________
>>
>> What would you do if you knew you could not fail?
>>
>>                                                   Author Unknown
>
>
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