Histograms of stellar age calculated from the TF parameters (left) and stellar age derived from the MAP values (right). The red and blue lines show the distribution of the Clean and Uncertain sample groups, respectively. We fit the purple shaded area with a log-normal function and plot the best-fit curve as the black solid line. The peak of the best-fit curve, denoted by a vertical black dotted line, is used as an average stellar age.