This is the case when presenting computer performance with respect to a reference computer, or when computing a single average index from several heterogeneous sources (for example, life expectancy, education years, and infant mortality).
這是情況下介紹電腦性能關於參考電腦，或者當計算一個平均索引從幾個異類來源 (例如, 壽命、受教育年限和嬰兒死亡率)。