Choose Language Hide Translation Bar
ana
ana
Community Trekker

Question in regards to Tukey's Multiple Comparisons Test

Hi there,

Would anyone be able to tell me how to go about running a Tukey's multiple comparisons test on my data? I've collected soils samples from 3 farming systems (n=3) on day 0, 14, and 28. I'm measured the cfu. I'm trying determine whether or not there's  a signifacant difference between the 3 farming systems on each collection date. I know there's no sig. dif. on day zero and I'm pretty sure there's a sig. dif. between the farming systems on day 14 and 28, I'm just not sure how to go about running the stat. analysis to prove that. I've inserted a photo of a graph and my data. Any help will be greatly appreciated!

 

Ana (my apologies if I posted this message in the wrong place)

Untitled-1.jpgUntitled-2.jpg

0 Kudos
1 ACCEPTED SOLUTION

Accepted Solutions
shoffmeister
Community Trekker

Re: Question in regards to Tukey's Multiple Comparisons Test

You can use a two-way-ANOVA the following way:

 

1. Main Menu => Analyze

2. Fit Model

 

Dialog.PNGFit Model Dialog (I like to use "Minimal Report")

 

3. In the fit-model dialog: Y is CFU

4. Select Farming System and Day => Macros => Factorial to Degree

5. Run

 

Then go to the main Hotspot (red triangle) next to Response CFU and select Estimates => Multiple Comparisons.

 

tuckey.PNG

Select the interaction term and "All Pairwise Comparisons - Tukey HSD". That will give you some tables and graphs to figure oput which groups are significantly different.

 

Hope that helps,

Sebastian

 

View solution in original post

3 REPLIES 3
shoffmeister
Community Trekker

Re: Question in regards to Tukey's Multiple Comparisons Test

You can use a two-way-ANOVA the following way:

 

1. Main Menu => Analyze

2. Fit Model

 

Dialog.PNGFit Model Dialog (I like to use "Minimal Report")

 

3. In the fit-model dialog: Y is CFU

4. Select Farming System and Day => Macros => Factorial to Degree

5. Run

 

Then go to the main Hotspot (red triangle) next to Response CFU and select Estimates => Multiple Comparisons.

 

tuckey.PNG

Select the interaction term and "All Pairwise Comparisons - Tukey HSD". That will give you some tables and graphs to figure oput which groups are significantly different.

 

Hope that helps,

Sebastian

 

View solution in original post

ana
ana
Community Trekker

Re: Question in regards to Tukey's Multiple Comparisons Test

Thank you SO much Sebastian! I really appreciate you taking the time to work out the steps. Ana
0 Kudos
Leycoste
Community Member

Re: Question in regards to Tukey's Multiple Comparisons Test

Hello and thank you for this explanation.

I had the same problem (ANOVA + Tukey, with weights in mices depending on the treatment).

However, can you help me to interpret the significant differences between the groups for each time?

what data should I look at for each week?

Thank you. 

 

To be clearer, I would like to know the p-value between each group for each week

 

Annotation 2019-05-14 103303.pngAnnotation 2019-05-14 103735.pngAnnotation 2019-05-14 103522.png

PS: I had no choice but to select the treatment on multiple comparisons

 

 

 

[EDIT] : Problem resolved. My variables (week) was not in "nominal".