A nice easy one about Repeated Measures ANOVA

#1
Hello!

A basic question from a not-very-statistically-savvy person:

I have data from 2 groups of patients who underwent knee replacement operations. One group was pre-conditioned (treatment) the other was not (control).

Blood samples were taken from both groups at 6 time-points (1 pre-op, 2 intra-op and 3 post-op).

From those samples the levels of various cytokines with funny names like IL-12p70 and IFN-y were measured.

I am considering each variable (cytokine) separately and thinking that a repeated measures ANOVA would be the appropriate test to do in order to compare the two groups, but I'm not sure...

Any thoughts would be much appreciated!
 
#2
Hi okennedy,

Are the cytokine levels the dependent variables?
And is treatment the only independent variable (other than time)?

If so, yes, you want repeated measures anova. In fact, it's a mixed model because time is within subjects (repeated) and treatment is between subjects.

Karen
 
#3
Hi Karen,

Yes, the cytokines are the dependant variables, and the treatment is the only independant variable other than time.

So, I'll give the mixed model repeated measures anova a go!

Thanks a million for your help, it is much appreciated.

Also, I've just signed up for Statwise - it is a great resource...I'm looking forward to the first newsletter!

Thanks again,

Oran
 
#5
Hi Karen,

Thanks, I'll look forward to that.

A quick follow-up question...if I may?

Resources over here are limited so I tried doing my analysis (two-factor ANOVA with repeated measures on one factor) using an online calculator...and I'm not sure if I'm using it correctly.

I have entered my data in a 2 row x 4 column structure. Where data in row 1 is control and row 2 is treatment. Each column is a different timepoint.

The result sheet has various values (SS, df, MS) among them are three F-values of 0.09 for A(between subjects) 2.68 for B(repeated measures variable) and 1.13 for AxB

So I think I'm either using this tool incorrectly or this experiment shows nothing of interest!

Here's hoping for the former...

Thanks again!

Oran
 
#6
Hi Oran,

I really can't tell you if you're doing it correctly. There are so many ways to set up the data--it differs for each program.

Usually each row in a data spreadsheet is a subject and each column is a variable, but even this can vary.

Karen