– 23 – Fig. 2.— Variability in the 3.6 µ m (top) and 4.5 µ m (bottom) channels as a function of magnitude for all objects with four epochs of data shown as contours. The objects are binned into 0.1 mag and 0.05 log( v ) bins. The contours are drawn for 2, 10, and 100 objects per bin, counting from the outer contour. The lower solid line shows the median v$_{m}$ calculated in 0.1 mag bins, and the upper three dashed, dash-dotted, and dotted lines show variability significances ( v − v$_{m}$ ) /σ = 1, 2, and 3 (from bottom to top) with respect to this median. We limit our Photometry Group 2 and 3 samples to objects with [3 . 6] < 19 . 7 mag, and [4 . 5] < 19 . 3 mag (vertical dashed lines). Dots mark ∼ 3200 Photometry Group 3 AGNs from the modified AGN wedge, selected as either X-ray or 24 µ m AGN candidates or having a QSO spectroscopic template code. Note that they tend to have higher average variability than the typical sources, but with amplitudes easily masked by the photometric uncertainties. Open circles mark objects with σ$_{12}$ > 10 and r > 0 . 8.