Beyond ANOVA (Part 7.4 a) {RMA Case-a}

[Neeraj Kaushik]

RMA Case (a): 1 measure with Only within group variations 

Attached file: repeat measure anova.sav
 
Background: Marks given by 4 teachers to 8 essays. 
Here each essay was evaluated by 4 teachers and we want to see whether there's any difference between the 4 teachers.
In this file, we've been given Gender also but we wont use it as of now.
 
Measure (Dep var): Marks
Within Sub Factor (Indep var): Teachers
No.of levels (How many teachers?): 4
 
Click on Analyze->General Linear Model->Repeated Measures
 
Within Sub Factor (Indep var): Teachers
No.of levels (How many teachers?): 4
Click on Add
 
Measure (Dep var): Marks
Click on Add
 
Click on Define
-----------------------
Send 'Teacher A' to 'Teacher D' to Right hand side pane
Click on Plots and send teachers to horizontal axis
Click on Add & then on Continue
 
Click on OK
 
----------------------
SPSS Output:
First table will give us the details  of Within subject factors.
We can skip the table-2 Multivariate tests also. Plz remember this table is just a supplemenary table.
 
Start by 3rd Table: Mauchly's test of sphericity
Sig value < 0.05 hence assumption violated.
So now see the value of Greenhouse Geisser measure. Its value is 0.558 (<0.75) so we'll use its value.
Go to nextx Table: Tests of within subjects effects
See the row of Greenhouse Geisser, its Sig value=0.63 
So there's no significant difference between the grades given by 4 teachers.  
 
In case we've different results given by Greenhouse-Geisser and Huynh-Feldt sig values then we shd use Table-2 (the reason being that table of MANOVA dnt use any such assumption of sphericity)
Now Pillai's trace suggests that infact there's no significant difference between the grades given by 4 teachers.
-----------------------------------------------------------
 
The other tables are useless, once we get that Null hypothesis is accepted. In other words, Other tables & menus will make sense only in case of rejection of H0.
 
However looking at plot it appears that there's a decrease in marks between teacher 1 & 2 & 4. But statistically these differences are not significant.
 
 
Happy learning
Neeraj

[Radha garg]

Respected Sir,

I think, there are some error which makes me confused.

1. There are 5 persons(a,b,c,d,e) rather than 4. So, i think there are 5 teachers.

2. The marks is given to four essays rather than 8. As if marks given to each essays by 5 teachers, then total entry of marks should be 8*5=40. But there are only 20 entry of marks. So, i think the marks is given for 4 essays and then total entry for is marks is 4*5=20.

Apart from that when we add the persons or marks (as per the lable)  in the subject factor or measure (dep. variable), then it shows error. furthermore, there is no such variable of teachers A to Teachers D to enter in right hand side pane.

But there are already entered over there. And the option of Ok, is also invisible. 

May be there can be some mistake in application part from my side, but i didn't understand the problem over here.

Thanks and Regards

Radha 

[Neeraj Kaushik]

Extremely Sorry Radha for attaching the wrong file (I've mentioned the name of the file but by mistake attached some other file)

--
You received this message because you are subscribed to the Google Groups "DataAnalysis" group.
To unsubscribe from this group and stop receiving emails from it, send an email to dataanalysistrai...@googlegroups.com.
For more options, visit https://groups.google.com/groups/opt_out.
 
 

[Radha garg]

Respected Sir,

Thanks for the file. Now, the concept is clear to me.

So, we can move ahead with the next example.

Regards

Radha 

To unsubscribe from this group and stop receiving emails from it, send an email to dataanalysistraining+unsub...@googlegroups.com.

[Neeraj Kaushik]

Dear Radha

Working on more than 1 example a day may lead to Statistical indigestion :-)
So next post tomorrow mrng.

KIT
Neeraj

To unsubscribe from this group and stop receiving emails from it, send an email to dataanalysistrai...@googlegroups.com.