condition mean min max ZT0-3 4.2957399999999994 4.2957399999999994 4.2957399999999994 ZT4-7 4.37133 4.37133 4.37133 ZT8-11 4.36312 4.36312 4.36312 ZT12-15 4.35162 4.35162 4.35162 ZT16-19 4.453906666666667 4.453906666666667 4.453906666666667 ZT20-23 4.31857 4.31857 4.31857