How to calculate mean in AWK

Another trick with awk to compute mean of a column.

Imagine that you have a file with many lines and you want to compute the mean of the fourth item on each line. E.g:

1 2 3

Lowest value found .2 Lowest value found .4 Lowest value found .6

Using the awk tool under Linux, type:

awk '{x+=$4; next} END{print x/NR}'
0.4