名校
1 . 为应对新一代小型无人机武器,某研发部门开发了甲、乙两种不同的防御武器,现对两种武器的防御效果进行测试.每次测试都是由一种武器向目标无人机发动三次攻击,每次攻击击中目标与否相互独立,每次测试都会使用性能一样的全新无人机.对于甲种武器,每次攻击击中目标无人机的概率均为
,且击中一次目标无人机坠毁的概率为
,击中两次目标无人机必坠毁;对于乙种武器,每次攻击击中目标无人机的概率均为
,且击中一次目标无人机坠毁的概率为
,击中两次目标无人机坠毁的概率为
,击中三次目标无人机必坠毁.
(1)若
,分别使用甲、乙两种武器进行一次测试.
①求甲种武器使目标无人机坠毁的概率;
②记甲、乙两种武器使目标无人机坠毁的数量为
,求
的分布列与数学期望.
(2)若
,且
,试判断在一次测试中选用甲种武器还是乙种武器使得目标无人机坠毁的概率更大?并说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/44fed1be8b7e50f18cb90077d9fce8e4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5e5db9fa0bc36e2308bd3eecd5e78351.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f9f0aaaa2695dff4b08d7a52e4c905e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/29be23f689eb01e57963495377501257.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/66577f4cb97c0d2a213ab1a9a02d1324.png)
(1)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f98df968dec4cb1b7e44cb47a5c216.png)
①求甲种武器使目标无人机坠毁的概率;
②记甲、乙两种武器使目标无人机坠毁的数量为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f022950e0faa45b617d497b01b5292b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f022950e0faa45b617d497b01b5292b9.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c4f2beb272e7c3342233f5cb681ac24.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8b70d4a3fc3e01b5a6358cf4e57578e6.png)
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3卷引用:山东省菏泽第一中学人民路校区2024届高三下学期5月月考数学试题
2024·全国·模拟预测
2 . 甲、乙两名小朋友,每人手中各有3张龙年纪念卡片,其中甲手中的3张卡片为1张金色和2张银色,乙手中的3张卡片都是金色的,现在两人各从自己的卡片中随机取1张,去与对方交换,重复
次这样的操作,记甲手中银色纪念卡片
张,恰有2张银色纪念卡片的概率为
,恰有1张银色纪念卡片的概率为
.
(1)求
的值.
(2)问操作几次甲手中银色纪念卡片就可能首次出现0张,求首次出现这种情况的概率
.
(3)记
.
(i)证明数列
为等比数列,并求出
的通项公式.
(ii)求
的分布列及数学期望.(用
表示)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3282e5fde4ae53fcb1bb072a685304c9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3ffb021aa7d5a5c2f0691e337caad624.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0ce603aa3abcb61750d2191aaa13dddc.png)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c7f66b7e38f44f8cd5d48b3aa24a20fc.png)
(2)问操作几次甲手中银色纪念卡片就可能首次出现0张,求首次出现这种情况的概率
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b1010846eeec6c9da29640f5aa3f8738.png)
(3)记
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9131abf93295537bbc0c54a8c42e88e2.png)
(i)证明数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4c895d4ce5ce82ef9b311b9369b4de11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(ii)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3282e5fde4ae53fcb1bb072a685304c9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
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3 . 在伯努利试验中,每次试验中事件
发生的概率为
(
称为成功的概率),重复该试验直到第一次成功时,进行的试验次数
的分布列为
,称随机变量
服从参数为
的几何分布,记作
.
(1)求证:
;
(2)设随机变量
表示试验直至成功与失败都发生时试验已进行的次数,求
的最小值;(参考公式:
)
(3)设随机变量
表示首次出现连续两次成功时所需的试验次数,求
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b1010846eeec6c9da29640f5aa3f8738.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/90d4c864a0ceec1585b87dc6cb3bc579.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f022950e0faa45b617d497b01b5292b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0c43d1bfa0445f9e2a7e52b6c83802d1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f022950e0faa45b617d497b01b5292b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b1010846eeec6c9da29640f5aa3f8738.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bdc1b34228c7b27714c3b57ccb6b084b.png)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7e3531f48b0ff955cf96e9ac1479e419.png)
(2)设随机变量
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a829fdd8ec0f3b7ede883cf2c3e53b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/71701db4b413f2364dbcbd612fbc8a67.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3a6cccc2739f1ced1f6c4cb0189154ef.png)
(3)设随机变量
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0d8b9ad2fcfff3dd546c5fdbedfe6238.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c60e1ba1988005e5fbf117f35762ff53.png)
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解题方法
4 . 如图,开车从
站到
站有3条路线.甲、乙、丙路线分别为![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4853b4705dee3de86e18a346ee3ae853.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8669a6aa7e782932422fe26986ff3dec.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/35ff324f42e4c0ebdc73afa6f3627a70.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9f4c4eb1dea2c12f31858ba9527c91.png)
.开车从
站到
站需要3分钟,从
站到
站需要2分钟,从
站到
站需要2分钟,从
站到
站需要,2.5分钟,从
站到
站需要
分钟,从
站到
站需要
分钟,从
站到
站需要
分钟,从
站到
站需要
分钟,受路上的红绿灯影响,
都是随机变量,且分布列如下
.
(1)若选择甲路线,开车从
站到
站的总时间为
分钟,求
的分布列;
(2)小张从这3条路线中选择1条,他在每站选择前进的方向时,都会等可能地选择其中一个方向,在他开车经过
站的前提下,若他开车从
站到
站的总时间少于5分钟的概率为0.4,求
的值;
(3)以各条路线开车需要的总时间的期望为依据,若三条路线中只有丙路线最快捷,求
的取值范围.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4853b4705dee3de86e18a346ee3ae853.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8669a6aa7e782932422fe26986ff3dec.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/35ff324f42e4c0ebdc73afa6f3627a70.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9f4c4eb1dea2c12f31858ba9527c91.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/35deedd73b1aa36be696a3674b87c0bc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/87c7eb49a823f757461cd5260757b088.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5cd84a8f95166367063218ee03ffd5a7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8db31d2bbc9b044646fd026f239e7b62.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0244fcb28c5a8fc66c4ba114162ee635.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/295fbfd4857081c1b7299a2247dae2f6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1a15534d805bcf37d4b8187def1cecd1.png)
2 | 2.5 | |
0.4 | 0.6 | |
1.5 | 2.5 | |
0.5 | 0.5 | |
2 | 3 | |
m | ||
2 | 3 | |
0.5 | 0.5 |
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f022950e0faa45b617d497b01b5292b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f022950e0faa45b617d497b01b5292b9.png)
(2)小张从这3条路线中选择1条,他在每站选择前进的方向时,都会等可能地选择其中一个方向,在他开车经过
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/294f5ba74cdf695fc9a8a8e52f421328.png)
(3)以各条路线开车需要的总时间的期望为依据,若三条路线中只有丙路线最快捷,求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/294f5ba74cdf695fc9a8a8e52f421328.png)
您最近一年使用:0次
2024-06-12更新
|
249次组卷
|
2卷引用:2024届广东省江门市新会华侨中学等校高考二模数学试题
名校
5 . 第二次世界大战期间,了解德军坦克的生产能力对盟军具有非常重要的战略意义.已知德军的每辆坦克上都有一个按生产顺序从1开始的连续编号.假设德军某月生产的坦克总数为N,随机缴获该月生产的n辆(
)坦克的编号为
,
,…,
,记
,即缴获坦克中的最大编号.现考虑用概率统计的方法利用缴获的坦克编号信息估计总数N.
甲同学根据样本均值估计总体均值的思想,用
估计总体的均值,因此
,得
,故可用
作为N的估计.
乙同学对此提出异议,认为这种方法可能出现
的无意义结果.例如,当
,
时,若
,
,
,则
,此时
.
(1)当
,
时,求条件概率
;
(2)为了避免甲同学方法的缺点,乙同学提出直接用M作为N的估计值.当
,
时,求随机变量M的分布列和均值
;
(3)丙同学认为估计值的均值应稳定于实际值,但直观上可以发现
与N存在明确的大小关系,因此乙同学的方法也存在缺陷.请判断
与N的大小关系,并给出证明.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8a5e1bb2637455d05313a112c5d745bc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/096b1ece1dcd29c59a46a4b3e02cb548.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e5031a3a951c4a1d1c5e9f80a5e26513.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/93d0f3799612b81e85b87241ec8eee68.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2dcf3400c1490071b390aaac0ad0e102.png)
甲同学根据样本均值估计总体均值的思想,用
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/afb1694f46c040a6c976b2ef3eb3934b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/120e4da3fe22be28b3bb28f28fbcc862.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/92da09d5877d3dfe1a856b6353b81906.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7b7171e0c9c26b9f39a32d3a61d113cf.png)
乙同学对此提出异议,认为这种方法可能出现
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b8a1bd336033c63bc9c4f99ff2b482b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ebcc133d5b11b33a904875182d8c8261.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be604061cf1591f7069472269d4c9719.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c50a1cf3b1a6f9a12605cbdf48e5de5c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49bf4a59874878184dadeec74d1781d2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/53722e8f43d44f9c611398ddaab151f3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/afac93e0089a7ffca9a1f720e13b6878.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/de3874d2e8c49308151837161d7aa91c.png)
(1)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ebcc133d5b11b33a904875182d8c8261.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be604061cf1591f7069472269d4c9719.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1b9b7c101f267bbf233da7d3ac30e6f0.png)
(2)为了避免甲同学方法的缺点,乙同学提出直接用M作为N的估计值.当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/270e5f2895909d5b6b6c612a8696565b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fac3649308b528fd56545ba102dc42d5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/348388b2590255369527f86fd6be63c3.png)
(3)丙同学认为估计值的均值应稳定于实际值,但直观上可以发现
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/348388b2590255369527f86fd6be63c3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/348388b2590255369527f86fd6be63c3.png)
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2024-06-11更新
|
703次组卷
|
3卷引用:浙江省(杭州二中、绍兴一中、温州中学、金华一中、衢州二中)五校联考2024届高考数学模拟卷
名校
解题方法
6 . 大连育明高级中学高三学生在交流2016年全国新课标Ⅲ卷单选压轴题时,各抒己见展示各自的解法.
题干:定义“规范01数列”
如下:
共有
项,其中
项为0,
项为1,且对任意
,
中0的个数不少于1的个数.若
,则不同的“规范01数列”共有[14]个.
A同学发现数据较少,可以列出所有情况,得到14个;
B同学在组合数学中学过卡特兰数,
,所以此题是
的情况,
.
在一次活动课上,甲、乙俩人设计了一个游戏,抛硬币一次,若正面向上加一分,反面向上减一分.若起始分为零分,出现负分游戏立刻停止.
(1)求在一次游戏中,恰好在第十一次后结束,中途只出现过两次零分的概率;
(2)如果一个人在一次游戏中,连续抛了十次硬币,求此时积分
的分布列和期望;
(3)参与一次游戏,记总共抛硬币次数为
,
的期望为
,求满足
的最小正整数
.
题干:定义“规范01数列”
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76aef4cdcb5af742ce28003b7b6c8c20.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76aef4cdcb5af742ce28003b7b6c8c20.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fad491e5b5e14c49ef8b7004ebcfcef9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/294f5ba74cdf695fc9a8a8e52f421328.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/294f5ba74cdf695fc9a8a8e52f421328.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fc07a2896f77eeb801584bcd92ff3791.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1232cb61b815cee8d87cf779d1d1cac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/711b21672fd907c5c92fee1d649e7003.png)
A同学发现数据较少,可以列出所有情况,得到14个;
B同学在组合数学中学过卡特兰数,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6fefd8e0dbfaac6f95c73ab1bde1072d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fac3649308b528fd56545ba102dc42d5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0c50c49328f9660f9b52aaad6794792.png)
在一次活动课上,甲、乙俩人设计了一个游戏,抛硬币一次,若正面向上加一分,反面向上减一分.若起始分为零分,出现负分游戏立刻停止.
(1)求在一次游戏中,恰好在第十一次后结束,中途只出现过两次零分的概率;
(2)如果一个人在一次游戏中,连续抛了十次硬币,求此时积分
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f022950e0faa45b617d497b01b5292b9.png)
(3)参与一次游戏,记总共抛硬币次数为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61b794ca545ebe0099d3e036a859fd06.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/069dfb6ecc2aa5803a2a45077468f68c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/09e392113d640a1d6709a6624ed10c1b.png)
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7 . 在坐标平面内
的区域,随机生成一个横纵坐标均为整数的一个整点![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3aac473ddb43914f7a4a5d142dd8dfbc.png)
,记该点到坐标原点的距离是随机变量X
相关公式:![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4bd9fe7e51b7aebba4012e077f621c02.png)
(1)当
时,写出X的分布列和期望.
(2)记随机变量
与
分别表示
的横纵坐标.
①求出
的期望 ![](https://staticzujuan.xkw.com/quesimg/Upload/formula/651127534574ec89f87fbe6223ded5bf.png)
②现在实际上选取了四个点
尝试运用样本的平均值去估计数学期望,以此来得到估计值
(四舍五入取整).
(3)记方差
,试证明
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/231b96ac0b7b1a9500b16b6f06da6949.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3aac473ddb43914f7a4a5d142dd8dfbc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c37784c634db2a54c7f1dc6951172a29.png)
相关公式:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4bd9fe7e51b7aebba4012e077f621c02.png)
(1)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/38c9d7f7f9a3e9ec476f5cf7fda97c88.png)
(2)记随机变量
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c94bb12cee76221e13f9ef955b0aab1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3aac473ddb43914f7a4a5d142dd8dfbc.png)
①求出
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/704f858f73063183e5779257900e694d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/651127534574ec89f87fbe6223ded5bf.png)
②现在实际上选取了四个点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4ea2bfe7ece5086158430c8487459f3e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/71dcc323aa6b7e73f92b2111cc4648be.png)
(3)记方差
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/406721302685612b54af3c223f059b8d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b958aecb5dc4ed0c6475f84e7eec5ca5.png)
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8 . 一口袋中装有10个小球,其中标有数字1,2,3,4,5的小球各两个,这些小球除数字外其余均相同.
(1)某人从中一次性摸出4个球,设事件A“摸出的4个球中至少有一个数字是5”,事件B“摸出的4个球中恰有两个数字相同”;分别求事件A和事件B的概率;
(2)现有一游戏,游戏规则是:游戏玩家每次有放回地从袋中随机摸出一球,若摸到5号球,则游戏结束;否则继续摸球,当摸到第
个球时,无论摸出的是几号球游戏都结束.设
表示摸球的次数
,求随机变量
的期望.
(1)某人从中一次性摸出4个球,设事件A“摸出的4个球中至少有一个数字是5”,事件B“摸出的4个球中恰有两个数字相同”;分别求事件A和事件B的概率;
(2)现有一游戏,游戏规则是:游戏玩家每次有放回地从袋中随机摸出一球,若摸到5号球,则游戏结束;否则继续摸球,当摸到第
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c4f27f84764f1cca89ce3d93fc1cf603.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f022950e0faa45b617d497b01b5292b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d9bb99dc0a8ae258016b8671527c367c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f022950e0faa45b617d497b01b5292b9.png)
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9 . 用n个不同的元素组成m个非空集合(
,每个元素只能使用一次),不同的组成方案数记作
例如,用1,2,3,4这4个元素组成2个非空集合共有7种方案,即
;
;
;
;
;
;
.于是
.
(1)求和:
;
(2)证明:当
时,
;
(3)某系列手办盲盒共装有4种不同款式的手办,打开其中任何一个盲盒都可以获得1个手办(款式随机,且获得每种款式的概率都相同)
①求购买该系列盲盒7盒就能集齐全部4种款式的概率p;
②设购买该系列盲盒7盒能获得不同手办款式的种类数为随机变量X,求X的数学期望
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/315109103349a6e41373c994e89f9f51.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca6d3696e6ff2775f4cde52a66a3dc53.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1cba028fe4a1f51166cf2492a5002183.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5c0a20cc4a02e6c8f4dfc71f3fb58b8d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/77b29beb494332847849d4725ea91ea6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b40289da7846a67d8905322ad257de95.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1a4a62a63babd750bc283099834a2373.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ebd2bbf4e475c3a9ed086cc6906cb87e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3957c2adc4e5f497ecc9d06c64c96f73.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1edc67d4416e549c2d01a82ac2f370d4.png)
(1)求和:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36901a78636c643523467783239274e2.png)
(2)证明:当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/33ed19a52f57f9edb69e52e3d7afef49.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/20f4077061e91eea5fbc73ab9aae7a54.png)
(3)某系列手办盲盒共装有4种不同款式的手办,打开其中任何一个盲盒都可以获得1个手办(款式随机,且获得每种款式的概率都相同)
①求购买该系列盲盒7盒就能集齐全部4种款式的概率p;
②设购买该系列盲盒7盒能获得不同手办款式的种类数为随机变量X,求X的数学期望
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5bf3baba074e8aeb6f3ea117865bbd1b.png)
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10 . 某手机App为了答谢新老用户,设置了开心大转盘抽奖游戏,制定了如下中奖机制:
每次抽奖中奖的概率为p,n次抽奖仍未中奖则下一次抽奖时一定中奖.每次中奖时有
的概率中积分奖,有
的概率中现金奖.若某一次中奖为积分奖,则下一次抽奖必定中现金奖,抽到现金奖后抽奖结束.
(1)若
,
,试求直到第3次才抽到现金奖的概率;
(2)若
,
,X表示抽到现金奖时的抽取次数.
(ⅰ)求X的分布列(用p表示即可);
(ⅱ)求X的数学期望
.(
,结果四舍五入精确到个位数)
每次抽奖中奖的概率为p,n次抽奖仍未中奖则下一次抽奖时一定中奖.每次中奖时有
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f89eef3148f2d4d09379767b4af69132.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f89eef3148f2d4d09379767b4af69132.png)
(1)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cc2d3df37e73a8abea815f37dbb3fff5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f970f380a12c843bb4a74ff34a15b2ac.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e1c3a498017612d64611d7f2dfb3a03e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/442770062ebcf26a09b5591a203fe1ff.png)
(ⅰ)求X的分布列(用p表示即可);
(ⅱ)求X的数学期望
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3b0919cf56a1b743189a019551b2d5a0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/30dd879b733f1c17313bbcb36a2c0761.png)
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