1. Miss White arranged 4 tests and an examination in English in the first school term .She considered the 4 tests as equally important.She considered the exam to be as important as the total of 4 tests .Susan got 76,87,48,97 marks in the four tests and 85 marks in the examination.Find her weighted mean mark.
2. I also want to ask when will I need to add units when calculating mean.median,and mode.
Thx
Weighted mean
2013-09-02 4:42 am
回答 (3)
2013-09-02 4:48 am
✔ 最佳答案
嘉麗 ，你好。1. 由於每個tests的比重一樣，可作四個tests的weighting 為1:1:1:1
至於考試的比重跟四個tests總共一樣，所以
Test 1 : Test 2 : Test 3 : Test 4 : Exam = 1:1:1:1:4
As a result, the weighted mean mark of Susan is
(1*76+1*87+1*48+1*97+4*85)/(1+1+1+1+4)
=81
2. You need the unit for the final answer (the unit can be like cm, m, degree, mL, etc.) However, as usual, you may omit the units during the steps (this is the common practice, but you can also list the unit for clarity)
簡單來說， mean, mode , median都是有單位的，最後答案請務必加上。
因為數學不單單是數字遊戲，而是要解決生活問題。
2013-09-23 7:34 am
Hi Godfrey,thx
2013-09-05 3:16 pm
除了 number (數字), ratio 例如 specific gravity (比重), 幾乎所有可測量的物質的量 (measurable physical quantity) 都有 unit (單位), 計算 mean, median, mode必有 unit.
問題在a set of data, 如果有部分 data 不同unit, 要將全部 data變為相同的 unit, 才可計 mean, median, ..
例子: 學生平均高度 5 ft, 5 ft 4 in, 5 ft 6 in, 6 ft, 5 ft 3 in
小心 derived unit km/h, m/s
問題在a set of data, 如果有部分 data 不同unit, 要將全部 data變為相同的 unit, 才可計 mean, median, ..
例子: 學生平均高度 5 ft, 5 ft 4 in, 5 ft 6 in, 6 ft, 5 ft 3 in
小心 derived unit km/h, m/s
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