12-15-2015 02:46 PM
The data that I am working with is egg production data over a course of 12 years. I was thinking of just taking the average flock production from the first and last year and putting it into a t-test to see if it was significantly different. My adviser thinks that there is probably some other type of modelling SAS can do for me that would provide me with more data. Do any of you good people happen know what that would be? (Broad question, I know).
I'm not very familiar with SAS at all and I haven't started working with it much yet. But I have to explain how I'm going to use SAS for a research proposal, which is a little hard when I don't entirely know how it works.
If anybody can help me get a better idea of what this modelling would look like compared to a T-test, that would be greatly appreciated!!
12-15-2015 03:19 PM
Your scientific hypotheses should not depend primarily on which statistical tools are available. You should state the hypotheses first and then ask: Can I use SAS to test them? Given the wide array of models that SAS can accomodate, the answer will depend mostly on your sampling plan and on the amount of data available.
12-15-2015 03:22 PM
Thanks for replying to me! My hypothesis isn't based on the stats available and that part is all done and sorted out. It's the materials and methods part of the proposal that this is going in where I need to be able to better explain what stats I plan on using.
12-15-2015 03:32 PM
All the egg production data is collected at the farm on a daily basis for every hen. It is stored in an Excel file and the data for each bird is broken down by number of eggs per week (ideal number being 7 eggs). I was going to take the files and chart the flock average for each breed of bird for every year to see if there were trends or spikes. Then I was going to take each breed average from the first year and run it through a t-test for each breed average for the most recent year.
12-15-2015 03:29 PM
The hypothesis is that since selection for the birds has not been based off of total egg production in the 12 generations we have had them, there will be no statisical difference between their total egg production from the year we first got the birds and now.
12-15-2015 04:06 PM
12-15-2015 04:15 PM
Yes, sorry, I should have explained that better, year and generation are basically interchangable in this case since we hatch out a new generation at the end of March every year and keep them around for a year before culling them to make space for the subsequent generation. All the birds are hatched on the same day so all of them are the same age for each generation.
12-15-2015 04:42 PM - edited 12-15-2015 04:48 PM
I think you should be using models for count data (individual bird annual production). You could test for differences between years (generations) and/or an overall time trend. The most appropriate SAS procedure for the task is proc glimmix, which unfortunately is not easy to use. So you might want to secure some help before you commit to it.
If you have a licence to SAS/ETS, you could use proc countreg, which is dedicated to count data analysis and a bit easier to master.
12-15-2015 05:08 PM
05-19-2017 02:05 AM
Hi @Justin_Allison, welcome to the SAS Forums.
If you'd like to post tutorial style posts, you can use an Article rather than create a thread or respond to a two year old thread.
Additionally, since you are new to the forums it would help if you post your links as full link rather than hyper link to first establish some trust. Many users will not click on a link where you cannot see the full address.
12-15-2015 03:21 PM