节: 平均 | 2.18 平均 | The Way To Learn

章节大纲

Bill coaches a baseball team. He has been keeping track all season of the total runs scored each game that his team plays. This is the list of data he has collected. Each number represents runs scored by his team in each game.
::Bill教棒球队。他一直在追踪球队球赛全赛季的成绩。这是他收集的数据列表。每个数字代表球队在每场比赛中得分的成绩。

2, 8, 8, 14, 9, 12, 14, 20, 19, 14

Bill wants to find the average amount of runs scored each game over the entire season.
::比尔想找到整个赛季每一场比赛的平均得分数

In this concept, you will learn how to find the mean, or average, of a set of number data.
::在此概念中,您将学会如何找到一组数字数据的平均值或平均值。

Mean
::平均平均

One way to analyze a set of number data is to find the mean . Another word for finding the mean is to find the average. An average combines numbers in the data set into one number that best represents the whole set.
::分析一组数字数据的方法之一是找到平均值。找到平均值的另一个词是找到平均值。平均将数据集中的数字合并成一个最能代表整个数据集的数字。

There are two steps to finding the mean.
::有两个步骤可以找到这个手段。

Add up all of the numbers in the data set.
::添加数据集中的所有数字。

Divide the total by the number of items (numbers) in the set.
::将总数除以集中的项目数(数量)。

Here is an example. This is a small data set to find the average.

10, 7, 3, 8, 2

First, add all the numbers together.
::首先,将所有数字加在一起。

$\begin{aligned} 10 + 3 + 7 + 8 + 2 = 30 \end{aligned}$

Next, divide the total, 30, by the number of items in the set. There are 5 numbers in the set, so divide 30 by 5.
::其次,将总数(30)除以集中的项目数量。集中共有5个,30个除以5个。

$\begin{aligned} 30 \div 5 = 6 \end{aligned}$

The mean, or average, of the set is 6.
::集的平均值或平均数是6。

Examples
::实例

Example 1
::例1

Earlier, you were given a problem about Bill and his baseball team's scores.
::早些时候,你得到一个问题关于比尔和他的棒球队的分数。

He wants to find the average number of runs his team scored throughout the season.
::他想找出整个赛季球队的平均跑步人数

2, 8, 8, 14, 9, 12, 14, 20, 19, 14

First, he adds up the values in the data set.
::首先,他把数据集中的数值加在一起。

$\begin{aligned} 2 + 8 + 8 + 14 + 9 + 12 + 14 + 20 + 19 + 14 & = 120 \end{aligned}$

Next, Bill divides the total by the number of games his team played this season. They played 10 games.
::接下来,Bill将总数除以他的球队本赛季玩的游戏数量。他们玩了10场。

$\begin{aligned} 120 \div 10 = 12 \end{aligned}$

Then, decide if the answer can be kept actual or needs to be rounded. In this case, the answer comes out as a whole number.
::然后,决定答案是实际的还是需要四舍五入的。在这种情况下,答案是一个整数。

The answer is that Bill's team scored an average (or mean) of 12 runs each game.
::答案是比尔的球队每场比赛平均得分12分

Example 2
::例2

Find the average of the data set below.
::查找以下数据组的平均数。

Jacob has the following quiz scores in his chemistry class for first quarter.
::Jacob第一季的化学课成绩如下

78, 90, 83, 88, 67, 90, 84, 69

What is Jacob's average for the quarter?
::雅各本季度的平均数是多少?

First, add up all of the scores.
::首先,加起来所有得分。

$\begin{aligned} 78 + 90 + 83 + 88 + 67 + 90 + 84 + 69 = 649 \end{aligned}$

Next, divide by the number of scores (in other words, the number of quizzes Jacob took).
::接下来,除以得分数(换句话说,雅各布考数数)。

$\begin{aligned} 649 \div 8 = 81.1 \end{aligned}$

Then, look at the quotient and decide if the answer should be a whole number rounded answer, or if it can be left as the exact decimal answer. It depends on the context of the data. In this case, all of Jacob's quiz scores were whole numbers so you can round the answer to a whole number as well.
::然后,看看商数,然后决定答案应该是一个整数四舍五入的答案,还是可以作为精确的十进制答案。它取决于数据的上下文。在这种情况下,雅各的所有测验分数都是整数,这样你就可以将答案与整数相圆。

The answer is that Jacob's average is an 81.
::答案是雅各布的平均数是81岁

Example 3
::例3

Find the mean of the following data set.
::查找以下数据集的平均值。

3, 4, 5, 6, 2, 5, 6, 12, 2

First, add the numbers in the data set together.
::首先,将数据集中的数字加在一起。

$\begin{aligned} 3 + 4 + 5 + 6 + 2 + 5 + 6 + 12 + 2 = 45 \end{aligned}$

Next, divide by the total number of items in the data set.
::其次,除以数据集中的项目总数。

$\begin{aligned} 45 \div 9 = 5 \end{aligned}$

Then, write your answer in either whole number or exact decimal form.
::然后,用整数或精确的十进制写出答案。

The answer is 5.
::答案是5。

Example 4
::例4

Find the mean of the following data set.
::查找以下数据集的平均值。

22, 11, 33, 44, 66, 76, 88, 86, 4

First, add the numbers in the data set together.
::首先,将数据集中的数字加在一起。

$\begin{aligned} 22 + 11 + 33 + 44 + 66 + 76 + 88 + 86 + 4 = 430 \end{aligned}$

Next, divide by the total number of items in the data set.
::其次,除以数据集中的项目总数。

$\begin{aligned} 430 \div 9 = 47.77 \end{aligned}$

Then, write your answer in either whole number or exact decimal form.
::然后,用整数或精确的十进制写出答案。

The answer is 47.8 or round up to 48.
::答案是47.8或四十八。

Example 5
::例5

Find the mean of the following data set.
::查找以下数据集的平均值。

37, 123, 234, 567, 321, 909, 909, 900

First, add the numbers in the data set together.
::首先,将数据集中的数字加在一起。

$\begin{aligned} 37 + 123 + 234 + 567 + 321 + 909 + 909 + 900 = 4000 \end{aligned}$

Next, divide by the total number of items in the data set.
::其次,除以数据集中的项目总数。

$\begin{aligned} 4000 \div 8 = 500 \end{aligned}$

Then, write your answer in either whole number or exact decimal form.
::然后,用整数或精确的十进制写出答案。

The answer is 500.
::答案是500

Review
::回顾

Find the mean for each set of data. You may round to the nearest tenth when necessary.
::查找每组数据的平均值。必要时,您可以四舍五入到最接近的十分之一。

4, 5, 4, 5, 3, 3

6, 7, 8, 3, 2, 4

11, 10, 9, 13, 14, 16

21, 23, 25, 22, 22, 27

27, 29, 29, 32, 30, 32, 31

34, 35, 34, 37, 38, 39, 39

43, 44, 43, 46, 39, 50

122, 100, 134, 156, 144, 110

224, 222, 220, 222, 224, 224

540, 542, 544, 550, 548, 547

762, 890, 900, 789, 780, 645, 700

300, 400, 342, 345, 403, 302

200, 199, 203, 255, 245, 230, 211

1009, 1000, 1200, 1209, 1208, 1217

2300, 2456, 2341, 2400, 2541, 2321

章节大纲

Mean ::平均平均

Examples ::实例

Example 1 ::例1

Example 2 ::例2

Example 3 ::例3

Example 4 ::例4

Example 5 ::例5

Review ::回顾

Mean
::平均平均

Examples
::实例

Example 1
::例1

Example 2
::例2

Example 3
::例3

Example 4
::例4

Example 5
::例5

Review
::回顾