I'm an applied statistics student trying to get help understanding some SAS output and how to correct a problem I'm having.  This is based on a hw problem I'm answering, but I promise if you answer I promise this doesn't violate any academic dishonesty policy or anything, the hw is not graded I just need to turn it in, but I want to try and get it correct and understand it before I do. Anyhow... This is based on based on Design and Analysis of Experiments by Angela Dean and Daniel Voss.  In an example in that text they describe how an equality of slopes test can be run on a covariate using the code: Proc GLM; CLASS COLOR; MODEL INFTIME=COLOR X COLOR*X; RUN; and the results: Source DF Sum of Squares Mean Square F Value Pr > F Model 7 273.2067301 39.0295329 5.97 0.0004 Error 24 157.0320199 6.5430008 Corrected Total 31 430.2387500 R-Square Coeff Var Root MSE INFTIME Mean 0.635012 12.63565 2.557929 20.24375 Source DF Type I SS Mean Square F Value Pr > F COLOR 3 127.6612500 42.5537500 6.50 0.0022 X 1 120.8353249 120.8353249 18.47 0.0002 X*COLOR 3 24.7101552 8.2367184 1.26 0.3108 Source DF Type III SS Mean Square F Value Pr > F COLOR 3 119.5483312 39.8494437 6.09 0.0031 X 1 132.2254691 132.2254691 20.21 0.0001 X*COLOR 3 24.7101552 8.2367184 1.26 0.3108 and that /*The interaction term X*COLOR will be significantly different from zero if the linear run order trends are not the same for each TRTMT.  (X is for run order)*/ Now, since the p-value for X*COLOR is 0.3108, the interpretation is that interaction is not significantly different from zero so the run order trends are the same for each TRTMT, meaning the equal slopes model can be used. My main problem is that I'm trying to run this same test on a different data set but when I run the test I have no error df and thus I get no F or p-values.  My code is: Proc GLM; class TRTMT; model ABSORB=TRTMT RATE TRTMT*RATE; run; my results are: Source DF Sum of Squares Mean Square F Value Pr > F Model 11 0.38463976 0.03496725 . . Error 0 0.00000000 . Corrected Total 11 0.38463976 R-Square Coeff Var Root MSE ABSORB Mean 1.000000 . . 0.466583 Source DF Type I SS Mean Square F Value Pr > F TRTMT 5 0.31614510 0.06322902 . . RATE 1 0.04055338 0.04055338 . . RATE*TRTMT 5 0.02794128 0.00558826 . . Source DF Type III SS Mean Square F Value Pr > F TRTMT 5 0.03317064 0.00663413 . . RATE 1 0.00221343 0.00221343 . . RATE*TRTMT 5 0.02794128 0.00558826 . . and then I can't make any conclusion.  How do I adjust in order to have error df.  My only thought is to also assign TRTMT as a covariate and then I get: Proc GLM; class ; model ABSORB=TRTMT RATE TRTMT*RATE; run; and Source DF Sum of Squares Mean Square F Value Pr > F Model 3 0.17898819 0.05966273 2.32 0.1517 Error 8 0.20565157 0.02570645 Corrected Total 11 0.38463976 R-Square Coeff Var Root MSE ABSORB Mean 0.465340 34.36306 0.160332 0.466583 Source DF Type I SS Mean Square F Value Pr > F TRTMT 1 0.00551384 0.00551384 0.21 0.6556 RATE 1 0.11543332 0.11543332 4.49 0.0669 TRTMT*RATE 1 0.05804103 0.05804103 2.26 0.1713 Source DF Type III SS Mean Square F Value Pr > F TRTMT 1 0.05991067 0.05991067 2.33 0.1654 RATE 1 0.11460643 0.11460643 4.46 0.0677 TRTMT*RATE 1 0.05804103 0.05804103 2.26 0.1713 Parameter Estimate Standard Error t Value Pr > |t| Intercept 4.348758487 1.81291361 2.40 0.0433 TRTMT -0.780015644 0.51094274 -1.53 0.1654 RATE -1.915624580 0.90724987 -2.11 0.0677 TRTMT*RATE 0.385052917 0.25625591 1.50 0.1713 and I can interpret that again in this data set interaction is not significant and thus the equal slopes model would be correct to use.  But, I don't think this is correct because TRTMT isn't supposed to be a covariate and by assigning it as such I think I'm completely changing the model. Thanks for any help you can give! ... View more

Below my code and attached is an excel document that contains the original SAS data set I am working with and the prints from my code.  In my code I have created a macro that will create and print a new data set based on a starting year, ending year, and a month.  The problem is that I want to be able to create multiple data sets at once by calling on more than one month at a time.  So in my code were I am using: %getSnowMonths() %getSnowMonths(Month = Jan) %getSnowMonths(Month = Feb) to create a data set for Dec (default) Jan, and February by calling on my macro 3 times, I want to be able to use %getSnowMonths(Month = Dec Jan Feb) to create the same data sets and prints. This is actually a problem from a homework assignment I am working on (and having some trouble with) for a Master's class.  Any suggestions or help would be appreciated.  Thanks! %macro getSnowMonths(data = "/courses/u_rit.edu1/i_581369/c_1057/wk3/rochestersnowfalltab.txt", yearStart=1905, yearEnd=1930, Month = Dec, prefix=Snow); data snow;       Infile &data Firstobs = 5  OBS = 122 DLM = '09'x;             Input Season 4. Sep Oct Nov Dec Jan Feb Mar Apr May Total;             If Sep = . then Sep = 0;             If Oct = . then Oct = 0;             If Nov = . then Nov = 0;             If Apr = . then Apr = 0;             If May = . then May = 0;       Options errors = 1000; Run; data &prefix&month&yearStart&yearEnd; set snow; keep Season &Month; where Season >=&yearStart and Season <=&yearEnd; run; Proc print data = &prefix&month&yearStart&yearEnd NoObs label; label &Month = 'Snow'; Title "Rochester Snowfall in &Month"; Footnote "Created on &sysday %sysfunc(today(), mmddyy10.) at &systime."; run; %mend getSnowMonths; %getSnowMonths() %getSnowMonths(Month = Jan) %getSnowMonths(Month = Feb) options symbolgen mprint; ... View more