Warning: file_put_contents(): Only 0 of 4994 bytes written, possibly out of free disk space in /home/www/wwwroot/zidian/69228.com/index.php on line 55 亚洲人成电影网站国产精品,无码国产精品一
The method that using weighted arithmetic average of class interval' class mid-value in computing the average is troublesome and is wrong. 運(yùn)用組距數(shù)列組中值加權(quán)算術(shù)平均法計算平均指標(biāo)比較麻煩，也容易出錯；