I have some data on the number of times each of my machines turned off (due to an error) in a particular time period. There are about 6 different classes of machines being used to construct a total population of 50 machines. I wanted to analyze the stability of the 6 classes of machine relative to each other.

An acquaintance suggested that I could do some heavy-hitter analysis during a brief chat to determine if some machines are shutting down more than others. Can someone tell me how to systematically perform this analysis or if there is a formal name for this kind of analysis?

  • $\begingroup$ I've never heard of this before, but perhaps this presentation will be of some help. "Frequent item analysis" seems to be the formal name. $\endgroup$ Jun 11, 2011 at 19:10

1 Answer 1


Upon digging deeper into this question, I figured out that this is nothing but extracting the heavy hitters (or the tail or the outliers) from the CCDF plot (which is 1-ECDF). If you are using R, one can do this in the following way:

Y = read.table(...)
Y.ecdf = ecdf(Y$V1)
curve((1-Y.ecdf(x)), n = 10000, 
       from = 0, to = 2600, ylab = "Pr(X > x)", 
       xlab = "x", col="blue", lty=1, lwd=2)

For example, the points on the extreme right (say from 80-100 but of course this is purely domain-specific) are the heavy-hitters or the tail of the curve.

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