为了找到一组数中的平均值或者说算术平均数，你所需要做的是把他们都加起来然后除以这些数字的个数。下文是如何做到这一点的方法。
步骤
方法 1 的 2:
第一部分：寻找平均值
-
{"smallUrl":"https:\/\/www.zenmeban.com\/images_en\/thumb\/3\/36\/Find-the-Average-of-a-Group-of-Numbers-Step-1-Version-3.jpg\/v4-460px-Find-the-Average-of-a-Group-of-Numbers-Step-1-Version-3.jpg","bigUrl":"https:\/\/www.zenmeban.com\/images\/thumb\/3\/36\/Find-the-Average-of-a-Group-of-Numbers-Step-1-Version-3.jpg\/v4-728px-Find-the-Average-of-a-Group-of-Numbers-Step-1-Version-3.jpg","smallWidth":460,"smallHeight":345,"bigWidth":728,"bigHeight":546,"licensing":"<div class=\"mw-parser-output\"><\/div>"}
1
找出集合中的数字的总和。你需要做的第一件事是把所有数字加起来。比如说，你要求出下面这些数字的平均值: 12， 33，26和11。你要把它们先加起来，12 + 33 + 26 + 11 = 82。
-
{"smallUrl":"https:\/\/www.zenmeban.com\/images_en\/thumb\/b\/b7\/Find-the-Average-of-a-Group-of-Numbers-Step-2-Version-3.jpg\/v4-460px-Find-the-Average-of-a-Group-of-Numbers-Step-2-Version-3.jpg","bigUrl":"https:\/\/www.zenmeban.com\/images\/thumb\/b\/b7\/Find-the-Average-of-a-Group-of-Numbers-Step-2-Version-3.jpg\/v4-728px-Find-the-Average-of-a-Group-of-Numbers-Step-2-Version-3.jpg","smallWidth":460,"smallHeight":345,"bigWidth":728,"bigHeight":546,"licensing":"<div class=\"mw-parser-output\"><\/div>"}
2
把这个结果除以这些数字的个数。集合中有4个不同的数字。所以，把这些数字总和82，除以4，获得平均值。82/4 = 20.5。这组数字的平均值为20.5。
方法 2 的 2:
第二部分：寻找加权平均值
-
{"smallUrl":"https:\/\/www.zenmeban.com\/images_en\/thumb\/8\/81\/Find-the-Average-of-a-Group-of-Numbers-Step-3-Version-3.jpg\/v4-460px-Find-the-Average-of-a-Group-of-Numbers-Step-3-Version-3.jpg","bigUrl":"https:\/\/www.zenmeban.com\/images\/thumb\/8\/81\/Find-the-Average-of-a-Group-of-Numbers-Step-3-Version-3.jpg\/v4-728px-Find-the-Average-of-a-Group-of-Numbers-Step-3-Version-3.jpg","smallWidth":460,"smallHeight":345,"bigWidth":728,"bigHeight":546,"licensing":"<div class=\"mw-parser-output\"><\/div>"}
1
写下每个类别的平均值。把所有数字加起来，然后除以数字的个数这个方法获得每组数字的平均值。比方说，你想找到一个班的加权平均值 ，下面是你将用到的数据和权重：
- 功课平均= 93％
- 测试平均= 88％
- 测验平均= 91％
-
{"smallUrl":"https:\/\/www.zenmeban.com\/images_en\/thumb\/c\/cc\/Find-the-Average-of-a-Group-of-Numbers-Step-4-Version-3.jpg\/v4-460px-Find-the-Average-of-a-Group-of-Numbers-Step-4-Version-3.jpg","bigUrl":"https:\/\/www.zenmeban.com\/images\/thumb\/c\/cc\/Find-the-Average-of-a-Group-of-Numbers-Step-4-Version-3.jpg\/v4-728px-Find-the-Average-of-a-Group-of-Numbers-Step-4-Version-3.jpg","smallWidth":460,"smallHeight":345,"bigWidth":728,"bigHeight":546,"licensing":"<div class=\"mw-parser-output\"><\/div>"}
2
写下每个类别的权重。 请记住，权重应增加高达100％。比方说，你正在计算下面的权重：
- 功课平均=最终成绩的30％
- 测试平均=最终成绩的50％
- 测验平均=最终成绩的20％
-
{"smallUrl":"https:\/\/www.zenmeban.com\/images_en\/thumb\/a\/a2\/Find-the-Average-of-a-Group-of-Numbers-Step-5-Version-3.jpg\/v4-460px-Find-the-Average-of-a-Group-of-Numbers-Step-5-Version-3.jpg","bigUrl":"https:\/\/www.zenmeban.com\/images\/thumb\/a\/a2\/Find-the-Average-of-a-Group-of-Numbers-Step-5-Version-3.jpg\/v4-728px-Find-the-Average-of-a-Group-of-Numbers-Step-5-Version-3.jpg","smallWidth":460,"smallHeight":345,"bigWidth":728,"bigHeight":546,"licensing":"<div class=\"mw-parser-output\"><\/div>"}
3
把每个类别乘以它的权重。现在，只需将各类别转换成十进制，然后把它乘以它所代表的平均值。在最后的成绩里30%就是0.3，或者3/10，50%就是0.5，或者5/10，20%就是0.2，或者2/10。现在，将这些十进制数字乘以他们所代表的平均值。
- 作业平均= 93×0.3 = 27.9
- 测试平均= 88×0.5 = 44
- 测验平均= 91×0.2 = 18.2
-
{"smallUrl":"https:\/\/www.zenmeban.com\/images_en\/thumb\/3\/3d\/Find-the-Average-of-a-Group-of-Numbers-Step-6-Version-2.jpg\/v4-460px-Find-the-Average-of-a-Group-of-Numbers-Step-6-Version-2.jpg","bigUrl":"https:\/\/www.zenmeban.com\/images\/thumb\/3\/3d\/Find-the-Average-of-a-Group-of-Numbers-Step-6-Version-2.jpg\/v4-728px-Find-the-Average-of-a-Group-of-Numbers-Step-6-Version-2.jpg","smallWidth":460,"smallHeight":345,"bigWidth":728,"bigHeight":546,"licensing":"<div class=\"mw-parser-output\"><\/div>"}
4
把所有结果相加。为了找到最后的权重，只需把那三个结果相加即可。27.9 + 44 + 18.2 = 90.1。最终加权平均的三组数字是90.1。
小提示
- 使用笔和纸 - 它将使你更加容易的计算。
- 大多数人倾向于使用平均值。