2017年GMAT數學基本概念解讀：統計

考生若想在GMAT數學考試中取得好成績，首先要掌握GMAT數學詞匯和基本概念，這樣才能又快又好完成GMAT數學題。這里優擇小編分享一下GMAT數學詞匯的相關內容。

gmat數學備考之描述統計(descriptive statistics)

1.平均數(average or arithmetic mean)

2.中數(median)

To calculate the median of n numbers，first order the numbers from least to greatest;if n is odd，the median is defined as the middle number，while if n is even，the median is defined as the average of the two middle numbers. For the data 6, 4, 7, 10, 4, the numbers, in order, are 4, 4, 6, 7, 10, and the median is 6, the middle number. For the numbers 4, 6, 6, 8, 9, 12, the median is (6+8 )/2 = 7. Note that the mean of these numbers is 7.5.

3.眾數(mode)：一組數中的眾數是指出現頻率最高的數。

例：the mode of 7，9，6，7，2，1 is 7。

4.值域(range)：表明數的分布的量，其被定義為最大值減最小值的差。

例：the range of–1，7，27，27，36 is 36-(-1)= 37。

5.標準方差(standard deviation)：

One of the most common measures of dispersion is the standard deviation. Generally speaking, the greater the data are spread away from the mean, the greater the standard deviation. The standard deviation of n numbers can be calculated as follows:

(1)find the arithmetic mean ;

(2)find the differences between the mean and each of the n numbers ;

(3)square each of the differences ;

(4)find the average of the squared differences ;

(5)take the nonnegative square root of this average.

Notice that the standard deviation depends on every data value, although it depends most on values that are farthest from the mean. This is why a distribution with data grouped closely around the mean will have a smaller standard deviation than data spread far from the mean.

GMAT數學的基本概念，如果考生加以歸類，會感覺沒有想象中那么復雜和混亂?？忌梢愿鶕w類的GMAT數學基本概念，加以復習和記憶。還要提醒考生的是，GMAT數學的基本概念，最忌諱的是死記硬背，考生最好采用理解式記憶法，GMAT數學基本概念就能輕松搞定。

想了解更多GMAT相關信息，歡迎咨詢優擇官網客服或撥打咨詢熱線：400-0341-885，我們有專業名師團隊對提出的問題進行一一解答，為您提供最優質的服務。

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