在GMAT数学部分的解题过程中，题目语言通常是国内考生们首先需要面对的大问题。为此，小编为大家整理了一些关于GMAT数学的一些概念。我们先来看看这些概念中的统计部分：
GMAT数学概念之统计(descriptive statistics)
1.平均数(average or arithmetic mean)
2.中数(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.众数(mode)：一组数中的众数是指出现频率最高的数。
例：the mode of 7，9，6，7，2，1 is 7。
4.值域(range)：表明数的分布的量，其被定义为最大值减最小值的差。
例：the range of–1，7，27，27，36 is 36-(-1)= 37。
5.标准方差(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.
大家只要在日常的备考过程中将GMAT数学概念加以归类和分析，思路就会更清晰。在这里小编想要告诉大家的是：对于GMAT数学概念切莫死记硬背，一定要在理解的基础进行记忆。只有这样才能真正的理解单词的含义，提高准确性。
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