obtained from equation (2) should be used if the collision strengths for Fe$^{+3}$ are wrong. If the collision strengths for Fe$^{++}$ are incorrect, the best values are those obtained from equation (2) lowered by 0.3 dex. And third, if the recombination coefficient or the rate of charge-exchange reaction for Fe$^{+3}$ are wrong, the ICF from equation (3) should be used. If there is a combination of causes for the discrepancy, the real iron abundance for each object will be intermediate between the two extremes given by the three values. Since equations (2) and (3) lead to different abundance distributions, and since we want to explore possible correlations with other parameters, we keep the individual abundances obtained from each ionization correction scheme, instead of just providing the average value.

Table \[tab:3\] shows the final abundances of oxygen and iron. The results shown for iron are the values obtained from equations (\[eq:1\]) and (\[eq:2\]). The third set of values, needed to constrain the iron abundances in the manner described above, can be obtained by subtracting $\sim 0.3$ dex to the values in column (3). Taking into account these three values, we constrain the iron abundances to the abundance range shown in column 