若<img src="https://img.ppkao.com/2017-07/jiangyouai/2017073016564366550.jpg" />都是总体参数q的无偏估计量,正确的说法是()。<p> 若<img src="https://img.ppkao.com/2017-07/jiangyouai/2017073016564366550.jpg" />都是总体参数q的无偏估计量,正确的说法是()。</p>
A、A.
B.
C.
D.
A、A.
B.
C.
D.
A、A.<img src="https://img.ppkao.com/2017-10/wangjinchen/2017101309154866509.jpg" />低电平,<img src="https://img.ppkao.com/2017-10/wangjinchen/2017101309155838776.jpg" />三态,<img src="https://img.ppkao.com/2017-10/wangjinchen/2017101309155342124.jpg" />低电平
B.<img src="https://img.ppkao.com/2017-10/wangjinchen/2017101309154866509.jpg" />三态,<img src="https://img.ppkao.com/2017-10/wangjinchen/2017101309155838776.jpg" />低电平,<img src="https://img.ppkao.com/2017-10/wangjinchen/2017101309155342124.jpg" />高电平
C.<img src="https://img.ppkao.com/2017-10/wangjinchen/2017101309154866509.jpg" />低电平,<img src="https://img.ppkao.com/2017-10/wangjinchen/2017101309155838776.jpg" />高电平,<img src="https://img.ppkao.com/2017-10/wangjinchen/2017101309155342124.jpg" />高电平
D.<img src="https://img.ppkao.com/2017-10/wangjinchen/2017101309154866509.jpg" />高电平,<img src="https://img.ppkao.com/2017-10/wangjinchen/2017101309155838776.jpg" />低电平,<img src="https://img.ppkao.com/2017-10/wangjinchen/2017101309155342124.jpg" />高电平
A、A.24A
B.-24A
C.<img src="https://img.ppkao.com/2017-12/xieqiushi/2017120714071740248.jpg" />
D.<img src="https://img.ppkao.com/2017-12/xieqiushi/2017120714072110716.jpg" />
A、A.<img src="https://img.ppkao.com/2018-08/lina/201808281525299943.jpg" />
B.<img src="https://img.ppkao.com/2018-08/lina/2018082815253315210.jpg" />
C.0
D.<img src="https://img.ppkao.com/2018-08/lina/2018082815253710704.jpg" />
E.<img src="https://img.ppkao.com/2018-08/lina/2018082815254216779.jpg" />
A、在一无限长的半圆形的金属薄片中,沿轴向流有电流,在垂直电流方向单位长度的电流为i=ksin<img src="https://img.ppkao.com/2018-08/lina/2018082909050377485.jpg" />,其中k为常数,<img src="https://img.ppkao.com/2018-08/lina/2018082909050377485.jpg" />如图所示,求半圆筒轴线上的磁感应强度。
<img src="https://img.ppkao.com/2018-08/lina/2018082909050635997.jpg" />
A、若经济变量y和x之间的关系为<img src="https://img.ppkao.com/2019-04/wangxuan/201904111525431527.jpg" />,其中A、α为参数,μi为随机误差,问能否用一元线性回归模型进行分析?为什么?
A、A.<img src="https://img.ppkao.com/2018-08/lina/2018082815072586879.jpg" />
B.<img src="https://img.ppkao.com/2018-08/lina/2018082815073054092.jpg" />
C.<img src="https://img.ppkao.com/2018-08/lina/2018082815073512842.jpg" />
D.<img src="https://img.ppkao.com/2018-08/lina/2018082815074194166.jpg" />
A、计算如下图所示电路中的电流I。
<img src="https://img.ppkao.com/2018-09/tangxueping/2018093017395879057.jpg" />
A、试用电源等效变换法求图示电路中的电流I。
<img src="https://img.ppkao.com/2018-09/lina/2018090210415085719.jpg" />
A、根据图所示电路,画出电压U和电流I的相量图。
<img src="https://img.ppkao.com/2018-09/wangjing/2018093014173883298.jpg" />
A、利用氧化还原电势表,判断下列反应能否发生岐化反应。
(a) 2Cu<img src="https://img.ppkao.com/2019-04/wangjing/2019041415353245090.jpg" />Cu + Cu2+
(b) Hg2+2<img src="https://img.ppkao.com/2019-04/wangjing/2019041415353245090.jpg" />Hg + Hg2+
(c) 2OH- + I2<img src="https://img.ppkao.com/2019-04/wangjing/2019041415353245090.jpg" /> IO- + I- + H2O
(d) H2O + I2<img src="https://img.ppkao.com/2019-04/wangjing/2019041415353245090.jpg" />HIO + I- + H+