4th-variance?

#1
Hello any and all,

I am no statistician so does the term "4th-variance" mean anything to someone? I am attempting to replicate the technique found in the publication below. The paper suggests that the 4th-variance is related to the expectation operator. The paper also discusses moment mathematics using kurtosis computation.

http://www.ijbem.org/volume6/number2/ding.pdf

Any help is appreciated.

Thanks.