Liaw, Andy schrieb:
>Ordinal variables should be stored as ordered factors in R. See ?ordered.
>
thnk`s for your reply. I tried to store as ordered factors
var <- as.ordered(var2)
but if I am calling the lm(dependent~var) I get a long list of values.
If I call
var <- as.numeric(var2)
lm(dependent~var)
then I get:
Residuals:
Min 1Q Median 3Q Max
-0.93563 0.01378 0.16272 0.25546 0.57862
Coefficients:
Estimate Std. Error t value Pr(>|t|)
(Intercept) 1.79513 0.02787 64.412 < 2e-16 ***
mean -0.28102 0.05993 -4.689 4.66e-06 ***
the SPSS call and Result is:
SPSS (13)
Analyse
General Linear Model
Univariate
Dependent Variable -> Dependent
Fixed Factors -> var2
OK
Tests of Between-Subjects Effects
Dependent Variable: dependent
| --------------- | ------------------------- | --- | ------------- |
-------- | ---- |
| Source | Type III Sum of Squares | df | Mean Square | F
| Sig. |
| --------------- | ------------------------- | --- | ------------- |
-------- | ---- |
| Corrected Model | 11,269(a) | 41 | ,275
| 1,668 | ,012 |
| --------------- | ------------------------- | --- | ------------- |
-------- | ---- |
| Intercept | 361,340 | 1 | 361,340 |
2193,088 | ,000 |
| --------------- | ----------------------- | --- | ----------- |
-------- | ---- |
| var2 | 11,269 | 41 | ,275 |
1,668 | ,012 |
| --------------- | ----------------------- | --- | ----------- |
-------- | ---- |
| Error | 31,964 | 194 | ,165
| | |
| --------------- | ----------------------- | --- | ----------- |
-------- | ---- |
| Total | 773,000 | 236 |
| | |
| --------------- | ----------------------- | --- | ----------- |
-------- | ---- |
| Corrected Total | 43,233 | 235 |
| | |
| --------------- | ----------------------- | --- | ----------- |
-------- | ---- |
a R Squared = ,261 (Adjusted R Squared = ,104)
Maybe anybody is able to show me the difference between SPSS and R calls
because the P value ic complete different
The url for the Data (if anybody would like to try)
http://biostatistic.de/temp/testr.csv
Regards Knut
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