When grouping by prefix characters, you must set the Interval to an integer.
当以前缀字符分组时，您必须将“间隔”设置为整数。
2
Design: a randomized and intervalgrouping design.
设计：随机区间分组设计。
3
The ichnofacies is the grouping of characteristic trace fossil association tending to rscirrence through a rather long interval of geologic time, and their environmental implication.