按GB3358—82《统计学名词及符号》的有关规定书写,常用如下:(1)样本的算术平均数用英文小写x(中位数仍用M);(2)标准差用英文小写s;(3)标准误用英文小写sx;(4)t检验用英文小写t;(5)F检验用英文大写F;(6)卡方检验用希文小写χ2;(7)相关系数用英文小写r;(8)自由度用希文小写υ;(9 According to the GB3358-82 “statistical terms and symbols,” the relevant provisions of writing, commonly used as follows: (1) the arithmetic mean of the sample in English lowercase x (median still use M); (2) standard deviation in English lowercase s; (3) standard misuse English lowercase sx; (4) t test in lowercase English t; (5) F test in uppercase F; (6) chi-square test with lowercase χ2; (7) r; (8) degrees of freedom with Greek lowercase υ;