Hello,
I've run a Proc Mixed function on a set of data in SAS.
The data was a result of an experiment that measured % viability over time and
I wanted to compare a Large sample lets say 50L to a small sample say 5L. And
compare the % viability between the 2 sizes to see if I get the same answer
there are 8 samples of each size and the same 8 samples are tested every day
over 10 days (day 0 - day 10).
Now, Given that the same bottles are repeatedly tested each day then doing an
ANOVA without taking account of the repeated measures nature of your experiment
could lead to erroneous conclusions. The problem is that when I test a bottle
11 times over so many days each recorded value from that bottle cannot be
considered statistically independent from the others. E.g. bottle A, day 0
the percentage recorded is high then it is more likely to be quite high on
day 2 than to be quite low hence the two measures are not statistically
independent.There are ANOVA models that can take account of repeated measures
I have used the SAS procedure Proc Mixed for this. And I have produced a
significant P-Value for size and not for time so I've shown there is an effect
of time but not for size. I have also produced confidence intervals for each
day over time how can I output the data in SAS to be read into R then plot a
graph of the confidence intervals??Also is there a way of doing this whole
analysis in R?Kind Regards,Al
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