condition mean min max ZT0-3 8.55724 8.55724 8.55724 ZT4-7 9.137008999999999 9.137008999999999 9.137008999999999 ZT8-11 8.383575 8.383575 8.383575 ZT12-15 8.6635375 8.6635375 8.6635375 ZT16-19 8.4597275 8.4597275 8.4597275 ZT20-23 8.0497215 8.0497215 8.0497215