What tests should I use for my statistical analyses

#1
Hello experts,
I have two groups of the spine: normative (n=8) and diseased (n=10) (unpaired)
each spine has five levels, (L=1,2,3,4,5)
So while those spines were growing I have measured 4 different types of heights (Right, Left, Anterior and Posterior) for each level: 1,2,3,4,5. those measurements were taken at four-time points for each spine (time in weeks): 7,11,14 and 28

I want to study the following:
1. The effect of level and time point on those four height measurements in both normative and diseased spines
2. The difference within each measurement as a function of level at all time points in normative and diseased spines
3. The difference within each measurement as a function of time point at all levels in normative and diseased spines
4. The difference in each measurement as a function of time point between normative and scoliotic spines
5. The difference in each measurement as a function of level between normative and scoliotic spines
As weight is correlated to age, should I consider weight as a covariate?
Moreover, I have performed a linear regression analysis to see the correlation between the heigh and the age,
6. I want to study the effect of the level on the intercept and the gradient

would you please help me with identifying the proper statistical tests?

Thank you I appreciate all your help, time and input
 

Karabiner

TS Contributor
#2
As far as I can see, basically you can use "mixed" analysis of variance
(repeated-measures ANOVA with 3 within-subjects factors and an
additional grouping factor). Of partcular importance will probably
be the interactions between the grouping factor and the respective
within-subjects factors.

With kind regards

Karabiner
 
#4
following up with my previous question, I have the following doubt please:
Can I still use mixed three-way ANOVA with repeated measures for my stats even if the height measurements were not taken for all the subjects at four-time points? for example, for one group of subjects height measurements were taken at four time points (7,11,14, 28), for a second group they were taken at three time points (11,14, 28) and for the third group at two time points (14, 28).
Moreover, should I take into my account that the differences between the time points are not equal? if yes what should I do about it?
Thanks,