Where the Error Falls Fastest

A model with one dial $w$ has its total error measured at five settings:

$w$	$0.0$	$0.5$	$1.0$	$1.5$	$2.0$
$E(w)$	$96$	$60$	$36$	$30$	$44$

Answer both parts:

(a) Over which of the four intervals is the error falling fastest, and at what average rate (in error units per unit of $w$ )?

(b) The model currently sits at $w = 2.0$ . Based on this table, should it increase or decrease $w$ to lower its error?