– 36 – Table 5. Mid-IR Variability by AGES Spectroscopic Classification. Variability Variability QSOs Stars Galaxies Level σ$_{12}$ Number (fraction/false positive rate) variable objects: Photometry Group 1 Total ... 2950 1121 18161 2 > 2 334 (11.3%/5%) 20 (1.8%/20%) 209 (1.1%/25%) 3 > 3 216 (7.3%/3%) 11 (1.0%/7%) 108 (0.6%/15%) 4 > 4 144 (4.9%/2%) 6 (0.5%/5%) 60 (0.3%/10%) Number (fraction/false positive rate) of variable objects: Photometry Group 2 Total ... 2820 966 17405 2 > 2 333 (11.8%/4%) 18 (1.9%/14%) 200 (1.1%/24%) 3 > 3 216 (7.7%/2%) 10 (1.0%/5%) 102 (0.6%/13%) 4 > 4 144 (5.1%/2%) 6 (0.6%/4%) 58 (0.3%/8%) Number (fraction/false positive rate) of variable objects: Photometry Group 3 Total ... 2192 491 11214 2 > 2 319 (14.6%/4%) 14 (2.9%/9%) 175 (1.6%/17%) 3 > 3 211 (9.6%/2%) 10 (2.0%/3%) 93 (0.8%/10%) 4 > 4 142 (6.5%/1%) 6 (1.2%/3%) 56 (0.5%/5%) Note. — The fraction of variable sources is a ratio of the number of variable objects above a given level of σ$_{12}$ and r > 0 . 8 to the total number of objects in a respective class. The false positive rate is estimated from the number of sources above the same level of σ$_{12}$ but with r < 0 . 5 (see Section 3 and Figure 3).