Re: [R] plotting residuals/error message

2014-03-16 Thread John Fox
Dear Jason,

Your suspicion is correct: the cases with NAs in either ft_dpc_r or pid_x
are absent from the residuals but not from pid_x. 

There are several ways to deal with this problem, but one straightforward
way is to use na.exclude in place of the default na.omit in the call to lm,
as in lm(ft_dpc_r~pid_x, na.action=na.exclude). Then residuals() will pad
out the values it returns with NAs.

I hope this helps,
 John

---
John Fox, Professor
McMaster University
Hamilton, Ontario, Canada
http://socserv.socsci.mcmaster.ca/jfox/



 -Original Message-
 From: r-help-boun...@r-project.org [mailto:r-help-bounces@r-
 project.org] On Behalf Of Gainous,Jason
 Sent: Saturday, March 15, 2014 1:42 PM
 To: r-help@r-project.org
 Subject: [R] plotting residuals/error message
 
 I am trying to plot the residuals from a linear model and I get the
 following error message: Error in xy.coords(x, y, xlabel, ylabel, log)
 :  'x' and 'y' lengths differ. The outcome is a continuous variable and
 the explanatory variable is ordinal. My immediate suspicion was that it
 had something to do with missing values. Each variable has missing
 values coded as NA. I can't figure it out. Please help. Thanks.
 
  obama.mod = lm(ft_dpc_r~pid_x)
  summary(obama.mod)
 
 Call:
 lm(formula = ft_dpc_r ~ pid_x)
 
 Residuals:
 Min  1Q  Median  3Q Max
 -89.271 -14.783   0.729  10.729  84.193
 
 Coefficients:
 Estimate Std. Error t value Pr(|t|)
 (Intercept) 101.5155 0.5797  175.12   2e-16 ***
 pid_x   -12.2441 0.1411  -86.76   2e-16 ***
 ---
 Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
 
 Residual standard error: 22.85 on 5876 degrees of freedom
   (36 observations deleted due to missingness)
 Multiple R-squared:  0.5616, Adjusted R-squared:  0.5615
 F-statistic:  7528 on 1 and 5876 DF,  p-value:  2.2e-16
 
  plot(pid_x, resid(obama.mod), ylab = Model Residuals)
 Error in xy.coords(x, y, xlabel, ylabel, log) :
   'x' and 'y' lengths differ
 
 
 Jason Gainous, Ph.D.
 Associate Professor
 Department of Political Science
 University of Louisville
 203 Ford Hall
 Louisville, KY 40292
 (502) 852-1660
 Homepage: https://louisville.academia.edu/JasonGainous
 
 
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Re: [R] plotting residuals/error message

2014-03-16 Thread Gainous,Jason
Thanks John. That worked. It was an easy solution. I'm in the process of 
switching from Stata and some of these small things are still hanging me up.

Jason 

-Original Message-
From: John Fox [mailto:j...@mcmaster.ca] 
Sent: Sunday, March 16, 2014 9:51 AM
To: Gainous,Jason
Cc: r-help@r-project.org
Subject: RE: [R] plotting residuals/error message

Dear Jason,

Your suspicion is correct: the cases with NAs in either ft_dpc_r or pid_x are 
absent from the residuals but not from pid_x. 

There are several ways to deal with this problem, but one straightforward way 
is to use na.exclude in place of the default na.omit in the call to lm, as in 
lm(ft_dpc_r~pid_x, na.action=na.exclude). Then residuals() will pad out the 
values it returns with NAs.

I hope this helps,
 John

---
John Fox, Professor
McMaster University
Hamilton, Ontario, Canada
http://socserv.socsci.mcmaster.ca/jfox/



 -Original Message-
 From: r-help-boun...@r-project.org [mailto:r-help-bounces@r- 
 project.org] On Behalf Of Gainous,Jason
 Sent: Saturday, March 15, 2014 1:42 PM
 To: r-help@r-project.org
 Subject: [R] plotting residuals/error message
 
 I am trying to plot the residuals from a linear model and I get the 
 following error message: Error in xy.coords(x, y, xlabel, ylabel, log)
 :  'x' and 'y' lengths differ. The outcome is a continuous variable 
 and the explanatory variable is ordinal. My immediate suspicion was 
 that it had something to do with missing values. Each variable has 
 missing values coded as NA. I can't figure it out. Please help. Thanks.
 
  obama.mod = lm(ft_dpc_r~pid_x)
  summary(obama.mod)
 
 Call:
 lm(formula = ft_dpc_r ~ pid_x)
 
 Residuals:
 Min  1Q  Median  3Q Max
 -89.271 -14.783   0.729  10.729  84.193
 
 Coefficients:
 Estimate Std. Error t value Pr(|t|)
 (Intercept) 101.5155 0.5797  175.12   2e-16 ***
 pid_x   -12.2441 0.1411  -86.76   2e-16 ***
 ---
 Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
 
 Residual standard error: 22.85 on 5876 degrees of freedom
   (36 observations deleted due to missingness) Multiple R-squared:  
 0.5616, Adjusted R-squared:  0.5615
 F-statistic:  7528 on 1 and 5876 DF,  p-value:  2.2e-16
 
  plot(pid_x, resid(obama.mod), ylab = Model Residuals)
 Error in xy.coords(x, y, xlabel, ylabel, log) :
   'x' and 'y' lengths differ
 
 
 Jason Gainous, Ph.D.
 Associate Professor
 Department of Political Science
 University of Louisville
 203 Ford Hall
 Louisville, KY 40292
 (502) 852-1660
 Homepage: https://louisville.academia.edu/JasonGainous
 
 
   [[alternative HTML version deleted]]
 
 __
 R-help@r-project.org mailing list
 https://stat.ethz.ch/mailman/listinfo/r-help
 PLEASE do read the posting guide http://www.R-project.org/posting- 
 guide.html and provide commented, minimal, self-contained, 
 reproducible code.

__
R-help@r-project.org mailing list
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.


Re: [R] plotting residuals/error message

2014-03-15 Thread Bert Gunter
Did you not notice:

Residual standard error: 22.85 on 5876 degrees of freedom
  (36 observations deleted due to missingness)

??
(No residuals for missings...)

-- Bert

Bert Gunter
Genentech Nonclinical Biostatistics
(650) 467-7374

Data is not information. Information is not knowledge. And knowledge
is certainly not wisdom.
H. Gilbert Welch




On Sat, Mar 15, 2014 at 10:42 AM, Gainous,Jason
jason.gain...@louisville.edu wrote:
 I am trying to plot the residuals from a linear model and I get the following 
 error message: Error in xy.coords(x, y, xlabel, ylabel, log) :  'x' and 'y' 
 lengths differ. The outcome is a continuous variable and the explanatory 
 variable is ordinal. My immediate suspicion was that it had something to do 
 with missing values. Each variable has missing values coded as NA. I can't 
 figure it out. Please help. Thanks.

 obama.mod = lm(ft_dpc_r~pid_x)
 summary(obama.mod)

 Call:
 lm(formula = ft_dpc_r ~ pid_x)

 Residuals:
 Min  1Q  Median  3Q Max
 -89.271 -14.783   0.729  10.729  84.193

 Coefficients:
 Estimate Std. Error t value Pr(|t|)
 (Intercept) 101.5155 0.5797  175.12   2e-16 ***
 pid_x   -12.2441 0.1411  -86.76   2e-16 ***
 ---
 Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

 Residual standard error: 22.85 on 5876 degrees of freedom
   (36 observations deleted due to missingness)
 Multiple R-squared:  0.5616, Adjusted R-squared:  0.5615
 F-statistic:  7528 on 1 and 5876 DF,  p-value:  2.2e-16

 plot(pid_x, resid(obama.mod), ylab = Model Residuals)
 Error in xy.coords(x, y, xlabel, ylabel, log) :
   'x' and 'y' lengths differ


 Jason Gainous, Ph.D.
 Associate Professor
 Department of Political Science
 University of Louisville
 203 Ford Hall
 Louisville, KY 40292
 (502) 852-1660
 Homepage: https://louisville.academia.edu/JasonGainous


 [[alternative HTML version deleted]]

 __
 R-help@r-project.org mailing list
 https://stat.ethz.ch/mailman/listinfo/r-help
 PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
 and provide commented, minimal, self-contained, reproducible code.

__
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.