假設比你A, B, C 三個數據(DATA)
而佢地重要性都唔同,例如A 重要過B (significance of A > significance of B),C就最唔重要
最重要既datum (A) 就佔最大比重; weight亦最大;
冇咁重要既data就weight會細啲 (現實世界中通常都係咁樣)
當我地想計一個數據既weighted value,我地直接乘返個數據落weight就得,i.e.
weighted value of a datum = value of datum * weight of datum
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但係單單呢個數字本身冇咩用,
加埋相關數據既weighted score,再除埋weight既總和(total weight = sum of weight),
就可以得到weighted average,睇到一個處理左既資料
weighted average of a set of data = sum of weighted value of a set of data / sum of weight
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eg, 我地當:
DATA NAME
| VALUE
| WEIGHT |
A
| 10 | 2.5 |
B | 20 | 1.5 |
C
| 30 | 0.5 |
咁 weighted value of A = 2.5 * 10 = 25
weighted value of B = 1.5 * 20 = 30
weighted value of C = 0.5 * 30 = 15
total weight = 2.5 + 1.5 + 0.5 = 4.5
weighted average = (25+30+15) / 4.5 = 15.555..