No idea how to perform my statistical analysis...

[hauptner]

Hello everybody!

I'm new here... I'm really need help with this issue... Now I am so lost that I do have no idea how to do the stats for one of my experiments... The experiment and the objective are as follow:

I wanted to know if the levels of a substance in colostrum affects the level of this substance in the serum of calves for the first 3 months of live. For it, I've got serum samples from 20 calves the day of birth and at different ages until 3 months and I analyzed this substance in the serum. As well, I took a sample of the colostrum fed the first day and analyzed the levels of this substance as well.

At the beginning I was thinking about running a repeated measurements ANOVA, but the thing is that I do have the levels of the substance as repeated measurements, but as calves only fed colostrum one time, I cannot treat this value as repeated measurements. Any idea about how can I study whether the levels of this substance in the colostrum fed the first day of live affect the progression of the levels of this substance during the first 3 months?

Any idea is welcome!! Many thanks!!!!!

[victorxstc]

It is interesting. I think although intoduction of this material to body affects the matching of your data, your data are still paired and repeated measures. Because so many other factors are still the same. Many authors correctly match different people only according to age or gender and run a repeated-measures test. So I think matching the data in your case is quite correct and suffices to use a repeated-measures test.

[hlsmith]

You almost have enough information here, but can you write it out as dependent variable and independent variable and the number of observations. At first glance it seems you are examining the impact on three different substances across time, independently? But, the first observations don't have all three substances? I am almost there, but confused enough to need some more info.

[Karabiner]

I wanted to know if the levels of a substance in colostrum affects the level of this substance in the serum of calves for the first 3 months of live.

That would be "level of substance in colostrum" as predictor
(independent variable), and the repeated serum measures as
dependent variable in a repeated measures ANOVA. I cannot
quite see where you are stuck.

Kind regards

K.

[hauptner]

Hi! Many thanks for your help!
I analyzed the levels of oxidants and antioxidants in the colostrum from each calf's dam and give it to the calves as a single meal, then I took serum samples from the calves at 7 different ages and analyzed the levels of oxidants and antioxidants in serum. I have no problem examining the oxidants/antioxidants throughout the 3 months period; but what I want to know is if the levels of pro- or antioxidants in the colostrum had an effect on the evolution of these parameters across time. I think that the dependent variables could be the pro- and antioxidants in serum and the independet variables the levels of pro- and antioxidants in colostrum. But I am not sure to do it in that way, because I have no repeated measurements for the colostrums, since the calves were fed with it only one time.

[hlsmith]

How many levels of antioxidants and levels of oxidant are there? If they both have one level, it is just simple repeated measures ANOVA, like you and Karabiner mentioned.

Dependent variable is measurements over time and independent variable is whether they were in the antioxidant or oxidant group. Pretty straightforward.

[hauptner]

Hi!! Many thanks for your help, but the think is that I do not have an oxidant and an antioxidant group. Each calf received the colostrum from his dam, and each colostrum have a different amount (the natural composition) of both antioxidants and pro-oxidants...

[hauptner]

The problem that I found is that I do not want to classify the calves in a high or low oxidative stress (relationship between antioxidant and oxidants) colostrum. Therefore I want to now if there is available any statistical analysis that allow me to use the value of antioxidants/oxidants in colostrum to see whether these levels have an effect on the evolution of the levels of the antioxidants/oxidants in serum... Any idea or suggestion?