i have uploaded X.txt (the cleaned data set) to the git repository also. I "attached" it when submitting the assigment on Coursera but it took >5 minutes to upload the file and the deadline expired during that time!!!! -- so am not sure if the file got attached. In case it is not, the same file can be got from github. Thanks.

PS:

I realized that the problem was with "summarize_each" function. It doesn't work as expected -- but summarise_each (British spelling) works. I found this the hard way -- after struggling for hours -- eventually found this info on stack overflow. I have now modified run_analysis.R to produce "part5.txt" -- which contains the tidy data as required in part 5 of the assignment. I an also putting prt5.txt in the git repository. Thanks for your patience.