A: Ce[img=17x22]1803dd552375aee.png[/img] + Fe[img=17x22]1803dd552ca7541.png[/img] = Ce[img=17x22]1803dd5534dbdef.png[/img] + Fe[img=17x22]1803dd553dc33d1.png[/img]
B: Ce[img=17x22]1803dd552375aee.png[/img] + Fe[img=17x22]1803dd553dc33d1.png[/img] = Ce[img=17x22]1803dd5534dbdef.png[/img] + Fe[img=17x22]1803dd552ca7541.png[/img]
C: Ce[img=17x22]1803dd5534dbdef.png[/img] + Fe[img=17x22]1803dd553dc33d1.png[/img] = Ce[img=17x22]1803dd552375aee.png[/img] + Fe[img=17x22]1803dd552ca7541.png[/img]
D: Ce[img=17x22]1803dd5534dbdef.png[/img] + Fe[img=17x22]1803dd552ca7541.png[/img] = Ce[img=17x22]1803dd552375aee.png[/img] + Fe[img=17x22]1803dd553dc33d1.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]
- 对电极反应反应Fe[img=17x22]1803dd593688451.png[/img]+e[img=11x21]1803dd593f0ee2e.png[/img]=Fe[img=17x22]1803dd5946fb818.png[/img]中有关离子浓度都减小一半时，φ (Fe[img=17x22]1803dd594f9ef1d.png[/img]/Fe[img=17x22]1803dd5958240ac.png[/img])的值不变。( )
- 反应MnO[img=11x26]1803dd597219875.png[/img]+5Fe[img=17x22]1803dd597aded1f.png[/img]+8H[img=11x21]1803dd5982f2487.png[/img][img=35x13]1803dd598a8157e.png[/img]Mn[img=17x22]1803dd59939f153.png[/img]+5Fe[img=17x22]1803dd599ce0266.png[/img]+4H[img=7x22]1803dd59a5ef6a0.png[/img]O构成电池，在标准状态下表示符号为（ ） A: （－）Pt︱Fe[img=17x22]1803dd59ae9d055.png[/img](c[img=11x21]1803dd59b70a07f.png[/img]), Fe[img=17x22]1803dd59bf2a421.png[/img](c[img=11x21]1803dd59c82f605.png[/img])‖MnO[img=11x26]1803dd59d0e7c34.png[/img](c[img=11x21]1803dd59d9cdd93.png[/img])，Mn[img=17x22]1803dd59e29bd7d.png[/img](c[img=11x21]1803dd59eb8a666.png[/img])︱Pt（+） B: （－）Pt︱MnO[img=11x26]1803dd59d0e7c34.png[/img](c[img=11x21]1803dd59d9cdd93.png[/img])，Mn[img=17x22]1803dd59e29bd7d.png[/img](c[img=11x21]1803dd59eb8a666.png[/img])‖Fe[img=17x22]1803dd59ae9d055.png[/img](c[img=11x21]1803dd59b70a07f.png[/img]), Fe[img=17x22]1803dd59bf2a421.png[/img](c[img=11x21]1803dd59c82f605.png[/img])︱Pt（+） C: （－）Pt︱Fe[img=17x22]1803dd59ae9d055.png[/img](c[img=11x21]1803dd59b70a07f.png[/img]), Fe[img=17x22]1803dd59bf2a421.png[/img](c[img=11x21]1803dd59c82f605.png[/img])‖Mn[img=17x22]1803dd59e29bd7d.png[/img](c[img=11x21]1803dd59eb8a666.png[/img])，MnO[img=11x26]1803dd59d0e7c34.png[/img](c[img=11x21]1803dd59d9cdd93.png[/img])︱Mn（+） D: （－）Pt︱MnO[img=11x26]1803dd59d0e7c34.png[/img](c[img=11x21]1803dd59d9cdd93.png[/img])，Mn[img=17x22]1803dd59e29bd7d.png[/img](c[img=11x21]1803dd59eb8a666.png[/img])‖Fe[img=17x22]1803dd59ae9d055.png[/img](c[img=11x21]1803dd59b70a07f.png[/img]), Fe[img=17x22]1803dd59bf2a421.png[/img](c[img=11x21]1803dd59c82f605.png[/img])︱Fe（+）
- 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]
内容
- 0
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]
- 1
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]
- 2
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]1803da11a68b020.png[/img]中, 是总体均值的无偏估计量. A: [img=17x22]1803da11b0fe561.png[/img]和[img=17x22]1803da11ba86065.png[/img] B: [img=17x22]1803da11c3301fe.png[/img]和[img=17x22]1803da11cc3e764.png[/img] C: [img=17x22]1803da11ba86065.png[/img]和[img=17x22]1803da11cc3e764.png[/img] D: [img=17x22]1803da11b0fe561.png[/img]，[img=17x22]1803da11ba86065.png[/img]和[img=17x22]1803da11cc3e764.png[/img]
- 3
下列各离子的电子排布式哪个是18电子构型。( ) A: Fe[img=17x22]1803dd5f3592d86.png[/img] B: Zn[img=17x22]1803dd5f3592d86.png[/img] C: Ca[img=17x22]1803dd5f3592d86.png[/img] D: S[img=17x22]1803dd5f5062b08.png[/img]
- 4
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]