Correlation between oxygen abundance and the gas fraction, μ. The dIs whose stellar masses were derived from sech magnitudes in ﹩K_{s}﹩ (Paper I) are plotted with circles, and those derived from 2MASS photometry are plotted with crosses. BCDs, all of whose stellar masses were derived from sech magnitudes in ﹩K_{s}﹩, are represented with triangles. ﹩T_{e}﹩‐based abundances are plotted as filled symbols and crosses, and ﹩R_{23}﹩‐based abundances are plotted as open symbols. The linear fit derived by Lee et al. (2003b) for his field dI sample is plotted with a dotted line. The gas fraction increases toward the left. Although there is a lot of scatter, most dIs and BCDs appear to follow the closed box model.