I am trying to evaluate a model by using the commands durbin.watson and cr.plot.
However, I keep getting errors that I can't figure out. A description follows. Does
anyone have a hint as to what may be wrong?
1)The Durbin Watson Test. In running the command I kept getting the
message "residuals include missing values" when actually this was NOT the
case.
Example:
>durbin.watson(hw8LM0)
Error in durbin.watson.lm(hw8LM0) : residuals include missing values
(2)Partial Residual Plots: Here I kept getting that the variables I choose
are not in the model, i.e. "Time is not in the model" when it clearly is.
Example:
>cr.plot(hw8LM0,variable="Time")
Error in cr.plot.lm(hw8LM0, variable = "Time") :
Time is not in the model.
Here is the model and residuals:
summary(hw8LM0)
Call:
lm(formula = Sales ~ Time)
Residuals:
Min 1Q Median 3Q Max
-516.32 -292.95 -29.15 238.48 895.09
Coefficients:
Estimate Std. Error t value Pr(>|t|)
(Intercept) 1418.872 122.464 11.59 2.35e-14 ***
Time 73.278 4.962 14.77 < 2e-16 ***
---
Signif. codes: 0 `***' 0.001 `**' 0.01 `*' 0.05 `.' 0.1 ` ' 1
Residual standard error: 389.8 on 40 degrees of freedom
Multiple R-Squared: 0.845, Adjusted R-squared: 0.8411
F-statistic: 218.1 on 1 and 40 DF, p-value: < 2.2e-16
hw8LM0$res
1 2 3 4 5 6
242.679535 679.531369 895.093204 442.975038 -237.443127 245.868708
7 8 9 10 11 12
82.540542 -13.347623 -209.325789 161.976046 -96.612120 -271.380285
13 14 15 16 17 18
-460.888451 -113.606616 -311.494782 -417.352947 -516.321113 1.430722
19 20 21 22 23 24
-18.407443 -328.425609 -476.743774 8.528060 67.849895 -298.548271
25 26 27 28 29 30
-478.826436 225.895398 110.617233 -226.800933 -487.939098 281.782736
31 32 33 34 35 36
-61.495429 -390.773595 -485.051760 431.670075 477.391909 -39.886256
37 38 39 40 41 42
-276.164422 732.557413 618.279247 -16.998918 -229.277084 756.444751
---------------------------------
Check out the new Yahoo! Front Page. www.yahoo.com/a
[[alternative HTML version deleted]]
______________________________________________
[EMAIL PROTECTED] mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
