[計量] 一題數學題

[ghtmmm (聖艾修伯里)]

In a quality-control test, 50 boxes-each containing 30 machine parts-were
examined for defective parts. The number of defective parts was recorded for
each box, and the average (arithmetic mean) of the 50 recorded numbers of
defective parts per box was 1.12. Only one error was made in recording the 50
numbers: "1" defective part in a certain box was incorrectly recorded as "10".

Quantity A
The actual average number of defective parts per box

Quantity B
0.94

答案是C
這題看好久還是不知道題目在問甚麼...

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→ suhorng     : 有50個箱子 每個箱子裡有30個機器
→ suhorng     : 這50個箱子中 缺陷品個數的平均是 1.12 個機器/箱
→ suhorng     : 不過計算缺陷品個數時 有一個 "1" 被錯置成了 "10"
→ ghtmmm      : THX~