Friedman test unreplicated complete block design error

Question

I\'m having trouble running a Friedman test over my data. I\'m trying to run a Friedman test using this command:

friedman.test(mean ~ isi | expId, data=monoS         


        

Answer 1

I don't get an error if I run your dataset:

   Friedman rank sum test

   data:  mean and isi and expId
   Friedman chi-squared = 17.9143, df = 3, p-value = 0.0004581

However, you have to make sure that expId and isi are coded as factors. Run these commands:

    monoSum$expID$<-factor(monoSum$expID)
    monoSum$isi$<-factor(monoSum$isi)

Then run the test again. This has worked for me with a similar problem.

Answer 2

I had this exact error too with my dataset. It turns out that the function friedman.test() accepts data frames (fx those created by data.frame() ) but not tibbles (those created by dplyr and other modern tools). The solution for me was to convert my dataset to a dataframe first.

D_fri <- D_all %>% dplyr::select(FrustrationEpisode, Condition, Participant)
D_fri <- as.data.frame(D_fri)
str(D_fri) # confirm the object should now be a 'data.frame'
friedman.test(FrustrationEpisode ~ Condition | Participant, D_fri)

Answer 3

Using the function as.matrix() to transform my dataframe is the magic that got the function to run for me.

Answer 4

Just thought I would mention I found this post because I was getting a similar error message. The above suggestions did not solve it. Strangely, I had to sort my dataframe so that block by block the groups appeared in order (i.e. I could not have the following: Block 1 A Block 1 B Block 2 B Block 2 A

It has to appear as A, B, A, B)

Answer 5

I know this is pretty old but for future generations (see also: me when I forget and google this again):

You can determine what the missing values are in your dataframe by running table(groups, blocks) or in the case of this question table(monoSum$isi, monoSum$expID). This will return a table of 0s and 1s. This missing records are in the the cells with 0s.

I ran into this problem after trying to remove the blocks that had incomplete results; taking a subset of the data did not remove the blocks for some reason.

Answer 6

I ran into the same cryptic error message in R, though in my case it was resolved when I applied the 'as.matrix' function to what was originally a dataframe for the CSV file I imported in using the read.csv() function.

I also had a missing data point in my original data set, and I found that when my data was transformed into a matrix for the friedman.test() call, the entire row containing the missing data point was omitted automatically.