condition mean min max ZT0-3 11.8784360185 11.01995623 12.736915807 ZT4-7 4.337021776 4.074485839 4.599557712999999 ZT8-11 6.925086455 5.290545431 8.559627479 ZT12-15 8.153329006500002 7.417071975000001 8.889586038000001 ZT16-19 8.917418497749999 8.685104465999999 9.1497325295 ZT20-23 8.627112281750001 8.483294473 8.7709300905