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如何评价试卷的质量,涉及到统计学中一个重要的概念,即相关和相关系数.相关是指两列变量之间的相互关系;相关系数是标志相关强度和方向的统计量数.一般采用“r”表示.其取值范围:-1.00≤r≤1.00.当两列变量变动方向相同时,称为正相关,r>0;当两列变量变动方向相反时,称为负相关,r<0;当两列变量之间毫无关系时,称零相关或无相关,r=0.其计算公式:
How to evaluate the quality of test papers involves an important concept in statistics, that is, correlations and correlation coefficients. Correlation refers to the relationship between two variables; correlation coefficient is the number of statistics that mark the strength and direction of correlation. r" said. Its range of values: -1.00 ≤ r ≤ 1.00. When the two columns of variable direction of the same change, known as positive correlation, r> 0; when the two columns of variables in the opposite direction, called negative correlation, r < 0; When there is no relationship between two columns of variables, they are called zero correlation or no correlation, r=0. Its calculation formula: