加入氨水即可进行分离的一组离子为( )。
A: Al[img=17x22]1803dd504e33cc2.png[/img]和Zn[img=17x22]1803dd5057444e5.png[/img]
B: Cu[img=17x22]1803dd50603b3f0.png[/img]和Ag[img=11x21]1803dd50694f4ca.png[/img]
C: Cd[img=17x22]1803dd507214d93.png[/img]和Ni[img=17x22]1803dd507b08b48.png[/img]
D: Fe[img=17x22]1803dd50839b07f.png[/img]和Al[img=17x22]1803dd508caf916.png[/img]
A: Al[img=17x22]1803dd504e33cc2.png[/img]和Zn[img=17x22]1803dd5057444e5.png[/img]
B: Cu[img=17x22]1803dd50603b3f0.png[/img]和Ag[img=11x21]1803dd50694f4ca.png[/img]
C: Cd[img=17x22]1803dd507214d93.png[/img]和Ni[img=17x22]1803dd507b08b48.png[/img]
D: Fe[img=17x22]1803dd50839b07f.png[/img]和Al[img=17x22]1803dd508caf916.png[/img]
举一反三
- 设总体X的分布律为P(X=0)=θ, P(X=1)=P(X=2)=(1-θ)/2，其中0<θ<1为待估未知参数。设[img=101x23]1802d3c6e1c13c2.png[/img]是简单随机样本。令[img=114x27]1802d3c6e985317.png[/img],[img=17x22]1802d3c6f1a9682.png[/img]为[img=101x23]1802d3c6e1c13c2.png[/img]中0所占的比例, 则以下哪个说法正确的？ A: [img=17x22]1802d3c702e42ee.png[/img]比[img=17x22]1802d3c70bb0618.png[/img]更有效 B: [img=17x22]1802d3c70bb0618.png[/img]和[img=17x22]1802d3c702e42ee.png[/img]都是[img=9x19]1802d3c72407a68.png[/img]的相合估计 C: [img=17x22]1802d3c70bb0618.png[/img]比[img=17x22]1802d3c702e42ee.png[/img]更有效 D: [img=17x22]1802d3c70bb0618.png[/img]是相合估计, [img=17x22]1802d3c702e42ee.png[/img]不是相合估计 E: [img=17x22]1802d3c70bb0618.png[/img]不是相合估计, [img=17x22]1802d3c702e42ee.png[/img]是相合估计 F: [img=17x22]1802d3c70bb0618.png[/img]， [img=17x22]1802d3c702e42ee.png[/img]都不是相合估计 G: [img=242x46]1802d3c7710420a.png[/img]
- 设X1，X2，X3是来自总体X的简单随机样本，则下列统计量[img=551x43]1803da166a9817a.png[/img]中, 是总体均值的无偏估计量. A: [img=17x22]1803da167310a8f.png[/img]和[img=17x22]1803da167bae41e.png[/img] B: [img=17x22]1803da168407eae.png[/img]和[img=17x22]1803da168b8a567.png[/img] C: [img=17x22]1803da167bae41e.png[/img]和[img=17x22]1803da168b8a567.png[/img] D: [img=17x22]1803da167310a8f.png[/img]，[img=17x22]1803da167bae41e.png[/img]和[img=17x22]1803da168b8a567.png[/img]
- 设X1，X2，X3是来自总体X的简单随机样本，则下列统计量[img=551x43]18033806cb7d6a4.png[/img]中, 是总体均值的无偏估计量. A: [img=17x22]18033806d402a81.png[/img]和[img=17x22]18033806dc38d57.png[/img] B: [img=17x22]18033806e4e5857.png[/img]和[img=17x22]18033806eda0c27.png[/img] C: [img=17x22]18033806dc38d57.png[/img]和[img=17x22]18033806eda0c27.png[/img] D: [img=17x22]18033806d402a81.png[/img]，[img=17x22]18033806dc38d57.png[/img]和[img=17x22]18033806eda0c27.png[/img]
- 设X1，X2，X3是来自总体X的简单随机样本，则下列统计量[img=551x43]1803da1393f5fdf.png[/img]中, 是总体均值的无偏估计量. A: [img=17x22]1803da139b3128e.png[/img]和[img=17x22]1803da13a44f014.png[/img] B: [img=17x22]1803da139b3128e.png[/img]和[img=17x22]1803da13b5b84de.png[/img] C: [img=17x22]1803da13a44f014.png[/img]和[img=17x22]1803da13b5b84de.png[/img] D: [img=17x22]1803da13d1416f1.png[/img]，[img=17x22]1803da13a44f014.png[/img]和[img=17x22]1803da13b5b84de.png[/img]
- 设X1，X2，X3是来自总体X的简单随机样本，则下列统计量[img=551x43]18035733a7a3c92.png[/img]中, 是总体均值的无偏估计量. A: [img=17x22]18035733b1e4eac.png[/img]和[img=17x22]18035733badf839.png[/img] B: [img=17x22]18035733c3a1aec.png[/img]和[img=17x22]18035733cbc1913.png[/img] C: [img=17x22]18035733badf839.png[/img]和[img=17x22]18035733cbc1913.png[/img] D: [img=17x22]18035733b1e4eac.png[/img]，[img=17x22]18035733badf839.png[/img]和[img=17x22]18035733cbc1913.png[/img]