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st: which statistics to use


From   "b. water" <barleywater@hotmail.com>
To   <statalist@hsphsun2.harvard.edu>
Subject   st: which statistics to use
Date   Mon, 22 Mar 2010 02:03:15 +0000

Dear all,
 
Stata 8.2,
 
I have data consisting of serum concentrations measured at regular intervals but under two different conditions (but a few missing reading here and there) like so:

 
  condition_1  condition_2
  t0 t1 t2 t0 t1 t2
sample_1 0.2 0.3 0.3 0.2 0.5 0.9
sample_2 0.7 0.7 0.9 0.7 1.2 1.3
.
.
.
.
.
.
sample_n 0.3 0.5 0.6 0.3 0.8 1.1

Just 'eye-balling' the data I can see that condition_2 did affect the concentrations. My questions:
 
1. How may I show that in condition_1 concentration at t1 and t2 _are_ statistically different from t0 (if indeed they are). Had it been just t0 with one other time interval, I would have thought of paired t-test off the bat but don't what to do in this circumstances. It looks like ANOVA but again would appreciate advice.
 
2. How may I show (statistically that is - and therefore what statistical analyses I should deploy) that w.r.t. t1 and t2 that condition_2 IS different from condition_1.
 
Thank you for advice/help.
 
bw  		 	   		  
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