两个均数的对比分析,即均数的显著性检验,可直接运用正态分布原理,以两个均数之差小于标准误的2倍为“相差不显著”;在2～3倍标准误之间者为“相差显著”;大于3倍标准误者为“相差非常显著”。另一种常用方法是应用 t 检验公式算出 t 值,然后查t值表或按孙一宋氏公式计算 t 值,再找出相应的概率 P。第一种适用于大样本(大于30例),后一方法 Comparison of the two means, that is, the significance of the test, can be directly applied to the principle of normal distribution, the difference between the two mean is less than 2 times the standard error is “not significantly different”; in 2 to 3 Times between the standard error is “significant difference ”; more than 3 times the standard error is “very different”. Another commonly used method is to use the t test formula to calculate the value of t, and then check the t value table or Sun’s formula to calculate the value of t, and then find out the corresponding probability P. The first applies to large samples (more than 30 cases), the latter method