=+49. The article cited in Exercise 21 also reported on another experiment in which the authors investigated whether the percent by weight of nickel in the alloy layer is affected by niobium powder paste thickness (A, at three levels), scanning speed (B, at three levels), and laser power (C, at three levels). One observation was made at each factor-level combination, yielding the accompanying data (Note: Thickness column headings were incorrect in the cited article):

Paste Thickness Power Speed .2 .3 .4 700 600 17.14 20.16 18.73 900 24.75 17.19 26.54 1200 18.78 18.80 21.42 800 600 26.55 13.03 18.92 900 19.96 29.37 21.41 1200 26.66 19.80 22.01 900 600 33.33 27.65 28.71 900 37.33 28.81 23.22 1200 34.98 26.40 15.44