若以下选项中的变量x1、x2、x3、x4均已正确定义,则合法的赋值语句是
举一反三
- 若以下变量均已正确定义并赋值，则合法的C语言语句是________。 A: a++; B: x = n % 2.5; C: x + n = i; D: x = 5 = 4 + 1;
- 设总体X服从均值为1/2的指数分布,X1,X2,X3,X4为来自X的样本,则X1,X2,X3,X4的联合概率密度为A.()正确B.()错误
- 设变量已正确定义,则正确的赋值语句为( ) A: x=26.3%3 B: 1+2=x2 C: x3=0*12 D: x4=1+2=3
- 继续上题，为了程序编写简洁，要给数据框x中的6列重新命名为x1,x2,x3,x4,x5,x6,应该使用的命令是（） A: ColNames(x) <- c("x1","x2","x3","x4","x5","x6") B: Names(x) <- c("x1","x2","x3","x4","x5","x6") C: colnames(x) <- c("x1","x2","x3","x4","x5","x6") D: colname(x) <- c("x1","x2","x3","x4","x5","x6")
- 【赋值语句】 若以下选项中的变量已正确定义，则正确的赋值语句是【 】 A: x1=26.8%3; B: 1+2=x2; C: x3=0x12; D: x4=1+2=3;