2. 职称英语
  3. [img]2015m7x/ct_egreqm_egreqtbz1_0073_20153[/img]Each of the people in three gr

[img]2015m7x/ct_egreqm_egreqtbz1_0073_20153[/img]Each of the people in three gr

游客2025-02-24  27
问题
Each of the people in three groups gave a rating of Product X on a scale from 1 through 5. For each of the groups, the table above shows the number of people in the group and the average(arithmetic mean)of their ratings. What is the average of the ratings of the product given by the 100 people in the three groups combined?
Give your answer to the nearest 0.1.
选项
答案 4.1
解析 For each of the three groups, the sum of the ratings given by the people in the group is equal to the number of people in the group times the average of their ratings. Therefore the sum of the ratings given by the 100 people in the three groups combined is 45(3.8)+ 25(4.6)+ 30(4.2), or 412, and the average of the 100 ratings is 412/100, or 4.12. Therefore, to the nearest 0.1, the correct answer is 4.1.
This explanation uses the following strategies.
Strategy 1: Translate from Words to an Arithmetic or Algebraic Representation
Strategy 4: Translate from a Figure to an Arithmetic or Algebraic Representation
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