12, 13, 14, 15, 16, 17, 18,的方差和标准差是多少要有过程?答:方差是每个数与平均值的差的平方的和 12, 13, 14, 15, 16, 17, 18的平均值为15 这方差=3²+2²+1²+0²+1²+2²+3²=28 标准差=√方差=√28=2√7
...8},{9,10,11,12}{13,14,15,16}},输出每行的平均值答:include <stdio.h> int main(void){ int a[4][4]={{1,2,3,4},{5,6,7,8},{9,10,11,12},{13,14,15,16}};int i, j;int sum;for (i = 0; i < 4; i++){ sum = 0;for (j = 0; j < 4; j++){ sum += a[i][j];} printf("第%d行平均值: %f\n", i+...
...8},{9,10,11,12}{13,14,15,16}},输出每行的平均值答:int main(void){int a[4][4]={{1,2,3,4},{5,6,7,8},{9,10,11,12},{13,14,15,16}};int i, j;int sum;for (i = 0; i < 4; i++){sum = 0;for (j = 0; j < 4; j++){sum += a[i][j];}printf("第%d行平均值: %f\n", i+1, sum / 4.0);}...