Print-tip LOWESS comparisons for BT-474_01 data This (A, M)-scatterplot shows a two-dimensional histogram  or all the spots for the first replicate BT-474 breast cancer hybridization, where the bright red color indicates a high concentration of spots. Print-tip k = 16 is highlighted by black dots. The LOWESS estimates obtained by using f16 = 0.2 are shown by the dark blue line and the estimates using optimal f16 is shown here in light blue. This result is typical for the print-tips in this study based on minimizing the cost function given in Eq. (5).