proc genmod data=want;

class period area;

model nsum=area period area*period / dist=NB link=log offset=log pop type1;

run;

I am not really interested in estimates just for area or just for period, rather, I am interested in the difference between the areas over the time period. In the output for the interaction of area*period, there are 3 rows for each year in the 17 year period so I have area 1, area 2, and area 3 (reference group). My question is - how do I interpret this output? Is there a way to broadly look at if the 3 areas differ significantly over this time period or do I have to look at the p-values for each year for areas 1 and 2 compared to the reference group?

I also have the LR statistics for type 1 analysis, but I'm not really sure what this is telling me when I look at the p-value for the area*period term. Thanks :) ]]>

So in excel you can use the Data Validation tool to create drop down lists to essentially force a user to have to enter a specific value in a cell.

I'm wondering if that can be done all from SAS? For example I want to have a question in column A and I want users to only be able to select Yes or No from a drop down list. I know how to do this in Excel directly, but wondering if it can be done from SAS?

Thanks! ]]>

I'm looking for help analyzing data. Here's the experimental setup:

12 experimental plots, divided into 3 blocks. Each block is a factorial combination of two treatments (precipitation, nitrogen).

Within each plot, I have 3-6 trees of species A and 3-6 trees of species B growing.

I measured tree height over time.

So, Block(1,2,3)>plot(pn,Pn,pN,PN)>treeID - Height(continuous response)

I'd like to conduct two sets of analyses:

1) Repeated Measures, Nested Mixed Model with block as a random factor, tree ID nested within plot, and time as the index of repeated measure.

This is the code I've written to attempt this:

PROC MIXED DATA=sgrowth ;

CLASS time plot species precipitation nitrogen treeID block;

MODEL height = species|precipitation|nitrogen|time;

REPEATED time / SUBJECT=treeID TYPE=CS;

RANDOM block block*nitrogen block*precipitation /SUBJECT= plot type=un;

run;

2) a Nested mixed model on data collected at the end of the experiment (no time component)

PROC MIXED data=seedlings ;

CLASS block plot precipitation nitrogen species;

MODEL height=precipitation|nitrogen|species /DDFM=bw;

RANDOM block block*precipitation block*nitrogen/ TYPE=un SUBJECT=plot;

run;

Are these constructed properly? Feedback is greatly appreciated! ]]>