R rmcorr 不正确的自由度数

Question

When I analyse raz2005 data from mrcorr package for repeated measures correlation with the following code:

brainvolage.rmc <- rmcorr (participant = Participant, measure1 = Age, measure2 = Volume, dataset = raz2005)

as given in the paper https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5383908/pdf/fpsyg-08-00456.pdf , I get df=71, which is correct since the number of participants is 72 in this data.

However, when I use the same code for my data, which is structured exactly like raz2005 , I get df=more than 400, although my participant number is 25. I use:

mydata.rmc <- rmcorr (participant = participant, measure1 = measure1, measure2 = measure2, dataset = mydata)

Answer 1

From the paper (page 7), the degrees of freedom should be calculated like this:

N = n_distinct(raz2005$participant)
k = nrow(raz2005)/N
df = N*(k-1)-1