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Logistic regression

Tara

July 22, 2013 09:00

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I am trying to preform logistic regression, but keep getting the message 'dependent variable value must be either zero or one'. I have entered a raster that has a one value for sites, and zero for everything else- what could I be doing wrong?

 

Thank you!

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8 comments

• 0
  
  idham khalil July 26, 2013 13:40

  Hi Tara,

  Sometimes, few pixels that is non-zero on one could interfere. Try to reclassify your raster into zero and one and repeat the regression.

   

• 0
  
  William Abel Villacrez Guerra February 16, 2014 05:05

  Hi Tara,

  idham khalil is right, I have another question , the independent variables have necessarily have values ​​from 0 to 255 ? or have to be binary ? , thanks for the reply

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  William Abel Villacrez Guerra February 17, 2014 03:16

  Hi Tara,

  I think you have to reclassify the raster of the dependent variable, I use Idrisi is same function but not if the independent variables have to be binary or should have a range of 0 to 255?.

  I hope you can help me.
  
  thanks

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  Clark Labs February 18, 2014 19:31

  Hi,

  Just to verify, yes Idham is correct. The dependent variable must be Boolean. But the independent variables can have any continuous range. Also consider using a mask to limit the analysis and not use background pixels that are not within the study area, if applicable. The use of this file is described in the Help.

  James Toledano

  Clark Labs

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  William Abel Villacrez Guerra February 20, 2014 05:35

  Hi,

  Thanks for your answer. Now I'm trying to make a logistic regression with data idrisi tutorial, generated all variables according to the tutorial but when running the model says: "A singular matrix has occured No meaningfull regression coefficients found Adjust the combination of the independent variables. " ¿which can be happening?

  Regards
  
  William Villacrez

• 0
  
  Clark Labs February 20, 2014 14:36

  Hi William, 

  There is another thread that deals with this issue that should help. In short, the message usually points to correlated independent variables. But no having sufficient sample size could lead to this issue. See the other thread on Logistic Regression in the forum on this. 

  https://forums.clarklabs.org/entries/40545866-Why-a-Logistic-Regression-be-interrupted-with-this-message-A-singular-matrix-has-ocurred-No-meaningf

   

  James Toledano

  Clark Labs

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  Apurba Sarkar July 30, 2019 21:24

  whene i run logistic regression in idrisi it give me only coefficient and standard deviation but no odda ration and standard error estimation how to calculate within idrisi

• 0
  
  Xu Tingting August 05, 2019 09:51

  Same question as Sarkar, how do we calculate the standard error and the significance levels of the regression coefficients with IDRISI?