[O III]/Hβ vs. [N II]/Hα, illustrating the positions of each refined activity class as predicted by our diagnostic tool (DONHa) after applying it on a sample of spectroscopically selected LINER galaxies. We utilized the DONHa classification scheme outlined in Table 3. The left, middle, and right panels indicates spectra excited by star formation (SB), AGN activity, and old stellar populations (Pas), respectively. The contours, symbols, and color-coding are as in Fig. 8. The black boundary lines are the same as defined in Fig. 2. The black dots represent the training sample for demonstration purposes.