assert.eq( 5 , Array.sum( [ 1 , 4 ] ), "A" )
assert.eq( 2.5 , Array.avg( [ 1 , 4 ] ), "B" )

arr = [ 2 , 4 , 4 , 4 , 5 , 5 , 7 , 9 ]
assert.eq( 5 , Array.avg( arr ) , "C" )
assert.eq( 2 , Array.stdDev( arr ) , "D" )