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]
举一反三
- 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]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]
- 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]
- 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]
内容
- 0
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]1802d3c4b0b57b7.png[/img]是简单随机样本。令[img=114x27]1802d3c4b95ff15.png[/img],[img=17x22]1802d3c4c1d3045.png[/img]为[img=101x23]1802d3c4b0b57b7.png[/img]中0所占的比例, 则以下哪个说法正确的？ A: [img=17x22]1802d3c4d3b0c4a.png[/img]是[img=9x19]1802d3c4dc1ecc6.png[/img]的无偏估计 B: [img=17x22]1802d3c4e500903.png[/img]是[img=9x19]1802d3c4dc1ecc6.png[/img]的无偏估计 C: [img=17x22]1802d3c4d3b0c4a.png[/img]不是[img=9x19]1802d3c4dc1ecc6.png[/img]的无偏估计 D: [img=17x22]1802d3c4e500903.png[/img]不是[img=9x19]1802d3c4dc1ecc6.png[/img]的无偏估计 E: [img=50x22]1802d3c51810ccd.png[/img] F: [img=50x22]1802d3c520b166f.png[/img] G: [img=50x23]1802d3c5296b22b.png[/img] H: [img=50x23]1802d3c532d0157.png[/img]
- 1
a,b为任意常数，且a[img=14x23]1803bbe371f8955.png[/img]0，则有D([img=10x14]1803bbe37a44e5d.png[/img]X +b)=[img=17x22]1803bbe3820329a.png[/img]D(X)
- 2
某质点在力[img=17x22]17e0abc8880d0f2.png[/img]=(4+5x)[img=12x22]17e0abc8931b224.png[/img] (SI)的作用下沿x轴作直线运动,在从x=0移动到x=10m的过程中,力[img=17x22]17e0abc8880d0f2.png[/img]所做的功为( ) 未知类型：{'options': ['', ' [img=39x19]17e0abc8a56adf1.png[/img]', ' [img=30x19]17e0abc8aec80f1.png[/img]', ' [img=30x19]17e0abc8b8bbed6.png[/img]'], 'type': 102}
- 3
设[img=173x71]1803d3572f2405f.png[/img],其中f(x)为连续函数,则[img=121x33]1803d357373930e.png[/img] A: [img=17x22]1803d35740393a3.png[/img] B: [img=49x27]1803d357489d00b.png[/img] C: 0 D: 不存在
- 4
原电池（-）Pt︱Fe[img=17x22]1803dd54de61136.png[/img](1 mol·L[img=17x22]1803dd54e7299c0.png[/img]),Fe[img=17x22]1803dd54f0030fb.png[/img](1 mol·L[img=17x22]1803dd54fa39c0d.png[/img])‖Ce[img=17x22]1803dd5502f9d6b.png[/img]( mol·L[img=17x22]1803dd550b82a7d.png[/img]) ,Ce[img=17x22]1803dd55130efd2.png[/img]( mol·L[img=17x22]1803dd551af174c.png[/img]) ︱Pt(+)的电池反应是( )。 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]