condition mean min max ZT0-3 31.185461 31.185461 31.185461 ZT4-7 17.71088 17.71088 17.71088 ZT8-11 13.897919 13.897919 13.897919 ZT12-15 16.8009125 16.8009125 16.8009125 ZT16-19 20.304549 20.304549 20.304549 ZT20-23 23.496289 23.496289 23.496289