variance between primary sample units

例句：

1. 1.The population of the city has a significant variance in age distribution.
   这个城市的人口年龄分布有显著的差异。
2. 2. Variations in temperature can affect the growth rate of crops.
   温度的变化会影响农作物的生长率。
3. 3. The variance between primary sample units is a critical factor in statistical analysis.
   主要样本单元之间的变异是统计分析中的关键因素。