a) Daily average 5–15 MeV n^-1 Fe intensities versus daily average C intensities. b) Daily average 5–15 MeV n^-1 Fe intensities versus daily average O intensities. In both figures, solar cycle 23 is shown in red and solar cycle 24 in blue. Days with fewer than two detected counts of C, O, or Fe are omitted. Linear fits in log-log scales and their slopes are shown. The quantities t and p represent a test statistic calculated for the difference of the slopes and the probability that such a difference would occur by chance. See Appendix A for details on the fitting and statistical testing.