condition mean min max ZT0-3 9.7232525 8.636705 10.8098 ZT4-7 8.554165 8.554165 8.554165 ZT8-11 7.776515 7.776515 7.776515 ZT12-15 0 0 0 ZT16-19 8.962485000000001 8.962485000000001 8.962485000000001 ZT20-23 8.519745 8.519745 8.519745