running_mean calculates the running mean in a vector with the given
bin width.
Usage
running_mean(v, binwidth)
Arguments
v
The numeric vector.
binwidth
Numeric constant, the size of the bin, should be meaningful,
ie. smaller than the length of v.
Value
A numeric vector of length length(v)-binwidth+1
Details
The running mean of v is a w vector of length
length(v)-binwidth+1. The first element of w id the average of
the first binwidth elements of v, the second element of
w is the average of elements 2:(binwidth+1), etc.