BookmarkSubscribeRSS Feed
AndresRod
Calcite | Level 5

Hello

 

I finished an experiment with two factors: 1) fertilization level and 2) With bacteria or without it.

So:

Fact. A (fertilization) = 100%,70%,30% y 0%  (four levels)
Fact. B (Bacteria) = Yes / No                            (two levels)

 

I have seven treatmentes, because I only have 100% without the bacteria. I took 4 measures duringin a month, each measure uses 6 plants per treatment.

T1: Withbacteria  / 0%fertilization   (6 plants/week) x (four weeks)

T2: NObacteria    / 0% fert.           (6 plants/week) x (four weeks)

T3: Withbacteria  / 30% fert        (6 plants/week) x (four weeks)

T4: NObacteria   /  30% fert       (6 plants/week) x (four weeks)
T5: Withbacteria  /  70% fert.     (6 plants/week) x (four weeks)
T6: NObacteria   /   70% fert     (6 plants/week) x (four weeks)
T7: NObacteria   /   100% fert.  (6 plants/week) x (four weeks)

 

I need help with my design and codes. Thank you.

1 REPLY 1
SteveDenham
Jade | Level 19

If you have access to Milliken and Johnson's Analysis of Messy Data, vol. 1, you could see their approach (termed a "means model") where they fit the response as the highest level interaction, and then create tests and contrasts to fit the research questions.  A google search on "means model" turned up a lot of hits.

.  Here is a link to an example, which would cover your whole plot analysis:

 

http://www.ats.ucla.edu/stat/sas/faq/cell_mean_coding_contrast.htm

 

Now, you have the additional design element of a repeated measures part, so you would need to port the code to PROC MIXED to correctly accommodate the covariance between the repeat measures.  Rather than ESTIMATE statments, LSMESTIMATE statements might be more useful.

 

I would suggest getting a whole plot analysis, and then sharing that code.  From there, we could craft PROC MIXED code to correctly handle the repeated part.

 

Steve Denham

sas-innovate-2024.png

Don't miss out on SAS Innovate - Register now for the FREE Livestream!

Can't make it to Vegas? No problem! Watch our general sessions LIVE or on-demand starting April 17th. Hear from SAS execs, best-selling author Adam Grant, Hot Ones host Sean Evans, top tech journalist Kara Swisher, AI expert Cassie Kozyrkov, and the mind-blowing dance crew iLuminate! Plus, get access to over 20 breakout sessions.

 

Register now!

What is ANOVA?

ANOVA, or Analysis Of Variance, is used to compare the averages or means of two or more populations to better understand how they differ. Watch this tutorial for more.

Find more tutorials on the SAS Users YouTube channel.

Discussion stats
  • 1 reply
  • 1148 views
  • 0 likes
  • 2 in conversation