condition mean min max ZT0-3 161.763329 161.763329 161.763329 ZT4-7 177.7788305 177.7788305 177.7788305 ZT8-11 158.18057199999998 158.18057199999998 158.18057199999998 ZT12-15 138.076735 138.076735 138.076735 ZT16-19 114.8526865 114.8526865 114.8526865 ZT20-23 103.350603 103.350603 103.350603