Returns the expected value of a degenerate distribution.
constant value of distribution
expected value
var v = mean( 0.1 ); // returns 0.1
var v = mean( 0.5 ); // returns 0.5
var v = mean( 10.0 ); // returns 10.0
var v = mean( NaN ); // returns NaN
Returns the expected value of a degenerate distribution.