<!-- /* Font Definitions */ @font-face	{font-family:"Cambria Math";	panose-1:2 4 5 3 5 4 6 3 2 4;	mso-font-charset:1;	mso-generic-font-family:roman;	mso-font-format:other;	mso-font-pitch:variable;	mso-font-signature:0 0 0 0 0 0;}@font-face	{font-family:Calibri;	panose-1:2 15 5 2 2 2 4 3 2 4;	mso-font-charset:0;	mso-generic-font-family:swiss;	mso-font-pitch:variable;	mso-font-signature:-520092929 1073786111 9 0 415 0;}@font-face	{font-family:"MS Shell Dlg 2";	panose-1:2 11 6 4 3 5 4 4 2 4;	mso-font-charset:0;	mso-generic-font-family:swiss;	mso-font-pitch:variable;	mso-font-signature:-520081665 -1073717157 41 0 66047 0;} /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal	{mso-style-unhide:no;	mso-style-qformat:yes;	mso-style-parent:"";	margin-top:0cm;	margin-right:27.35pt;	margin-bottom:0cm;	margin-left:0cm;	margin-bottom:.0001pt;	mso-pagination:widow-orphan;	font-size:12.0pt;	mso-bidi-font-size:11.0pt;	font-family:"Times New Roman","serif";	mso-fareast-font-family:Calibri;	mso-fareast-theme-font:minor-latin;	mso-bidi-font-family:"Times New Roman";	mso-bidi-theme-font:minor-bidi;	mso-fareast-language:EN-US;}.MsoChpDefault	{mso-style-type:export-only;	mso-default-props:yes;	mso-ascii-font-family:Calibri;	mso-ascii-theme-font:minor-latin;	mso-fareast-font-family:Calibri;	mso-fareast-theme-font:minor-latin;	mso-hansi-font-family:Calibri;	mso-hansi-theme-font:minor-latin;	mso-bidi-font-family:"Times New Roman";	mso-bidi-theme-font:minor-bidi;	mso-ansi-language:EN-US;	mso-fareast-language:EN-US;}.MsoPapDefault	{mso-style-type:export-only;	margin-right:27.35pt;}@page WordSection1	{size:612.0pt 792.0pt;	margin:72.0pt 72.0pt 72.0pt 72.0pt;	mso-header-margin:36.0pt;	mso-footer-margin:36.0pt;	mso-paper-source:0;}div.WordSection1	{page:WordSection1;}-->Hello,Iam trying to take the information from the summary of my best fit logisticregression model for the occurrence of a high elevation plant spp. and createthe appropriate equation that will calculate probability of occurrence, given thedata. My predictors include both continuous variables (slope and a second orderpolynomial of elevation) and a discrete variable for aspect (warm and cool). Ihave left unchanged the default contrasts option, so I believe that thefollowing coefficients were created using treatment contrasts.  Myquestion how can I take this summary output and create the logistic equationthat will allow me to calculate probability of occurrence. My interests are touse this to spatially display this info in a GIS environment. I have made adraft equation (shown below) that uses the coefficients from this summaryoutput, but this appears to be incorrect – values always return zeroprobabilities. Presumably I need to adjust the values in some way – but I amunclear as to how to proceed. Anyguidance would be appreciated!  >summary (model.Slope.Elevation.Aspect) Call:glm(formula= Po ~ Slope + poly(Elevation, 2) + Aspect_2, family = quasibinomial) DevianceResiduals:     Min      1Q   Median       3Q     Max  -1.0532  -0.4167 -0.2760  -0.1823   3.3376  Coefficients:                      Estimate Std. Error t valuePr(>|t|)    (Intercept)          -4.577707   0.222406 -20.583  < 2e-16 ***Slope                 0.039959   0.003593 11.121  < 2e-16 ***poly(Elevation,2)1   8.050898   5.601956  1.437   0.1508    poly(Elevation,2)2 -37.694521   6.297806  -5.985 2.39e-09 ***Aspect_2w             0.429229   0.174760  2.456   0.0141 *  ---   (1/ (1 +  exp(-1 * (-4.577707 + 0.039959*Slope + 8.050898 * poly(Elevation, 2)1 + -37.694521 * poly(Elevation, 2)2 + 0.429229* Aspect_2w))))) 

Brendan Wilson
2530 Alexis Road
Shoreacres BC 
Canada  V1N 4P6
Ph: 1.250.359.5905



	[[alternative HTML version deleted]]

