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X~2测验是1899年 Pearson 所提出的一个测量实际值和理论值之间的偏离度的判据。X~2是一种统计量,它的定义是:X~2=∑(实际值-理论值)~2/理论值=∑(A-T)~2/T式中 X~2为卡方值,∑为总和,(A-T)~2为实际值与理论值差数的平方。X~2值的大小与(A-T)~2成正比。这是 X~2测验的基本公式。在医学科学研究工作中,X~2测验通常用于计数资料中两个或两个以上样本率之间的显著性测验,是一种用途较广的显著性测验方法之一。其特点可以不通过百分率而直接
The X ~ 2 test is a criterion proposed by Pearson in 1899 to measure the degree of deviation between the actual value and the theoretical value. X ~ 2 is a statistic, which is defined as: X ~ 2 = Σ (actual value - theoretical value) ~ 2 / theoretical value = Σ (AT) ~ 2 / T where X ~ 2 is a chi square value, Σ is the sum, (AT) ~ 2 is the square of the difference between the actual value and the theoretical value. The value of X ~ 2 is proportional to (A-T) ~ 2. This is the basic formula of X ~ 2 test. In medical research, the X ~ 2 test is usually used for counting the significance of two or more samples between the test, is a wide range of significance test methods. Its characteristics can not directly through the percentage