No variables were entered into the equation SPSS

[mimi]

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[Eric Black]

Did you check whether the listwise deletion causes no valid cases to be left?

[David Marso]

That's the program's way of telling you that there is no discernible linear relationship between yield and any of your predictors .
A quick check reveals that this is precisely the case.

On the bright side.  You don't have to spend a lot of time writing up the results.


Simple pairwise correlations.
--
Correlations
yield
        Pearson Correlation Sig. (2-tailed) N
yield 1 13
Mon65 .251 .409 13
Mon60 .222 .466 13
Mon55 .216 .479 13
Mon50 .216 .479 13
Tue65 -.036 .908 13
Tue60 .052 .867 13
Tue55 .072 .814 13
Tue50 .048 .875 13
Wed65 -.189 .537 13
Wed60 .025 .934 13
Wed55 .123 .688 13
Wed50 .228 .455 13
Thu65 .144 .639 13
Thu60 .314 .297 13
Thu55 .430 .142 13
Thu50 .447 .126 13
--
OK:  I actually examined the data itself (unusual for me -I'm more of a data butcher than a stats cat,  I know a lot about stats but typically I stay out of such discussions because IMNSHO, there is usually insufficient info to justify meddling (without substantial prodding) and mostly my best advice is to hire a qualified local advisor (which I guess is not what people want to hear!-).  
In this case it is flat out simple.  Nothing to see here.

Eric Black wrote

Did you check whether the listwise deletion causes no valid cases to be left?

[Bruce Weaver]

  /CRITERIA=PIN(.05) POUT(.10)

I suspect that if you ran a simple linear regression (i.e., one-predictor model) for each predictor, you would find that none of them are significant at the .05 level.

But you have much bigger fish than that to fry.  First, see these comments on why stepwise selection is almost always unwise:

  http://www.stata.com/support/faqs/statistics/stepwise-regression-problems/

Second, you have only 13 cases in your data file!  With such a small sample size, you might be able to fit a reasonable one-predictor model.  But trying to include multiple predictors is not advisable.  See Mike Babyak's nice article on over-fitting regression models:

  http://people.duke.edu/~mababyak/papers/babyakregression.pdf

HTH.

mimi wrote

Hi all,
I am trying to run a stepwise regression, I chose Analyze, I entered the variables, I ran the STEPWISE option analysis. The output screen indicates the following:
REGRESSION
  /DESCRIPTIVES MEAN STDDEV CORR SIG N
  /MISSING LISTWISE
  /STATISTICS COEFF OUTS CI(95) R ANOVA COLLIN TOL ZPP
  /CRITERIA=PIN(.05) POUT(.10)
  /NOORIGIN
  /DEPENDENT yield
  /METHOD=STEPWISE Mon65 Mon60 Mon55 Mon50 Tue65 Tue60 Tue55 Tue50 Wed65 Wed60 Wed55 Wed50 Thu65 Thu60 Thu55 Thu50
  /SCATTERPLOT=(*ZPRED ,*ZRESID)
  /RESIDUALS DURBIN HISTOGRAM(ZRESID) NORMPROB(ZRESID).
   
 

Warnings
No variables were entered into the equation.

 I appended the Data. Could you tell me what I am doing wrong?
Thanks in advance.
Data.xls

[mimi]

Thank you.