设随机变量服从X~B(2,P),Y~B(3,P),若P(X≥1)= 7 16 ,则P(Y=2)= 设随机变量X~B(2,p),Y~B(3,p),若P(X≥1)...
\u8bbe\u968f\u673a\u53d8\u91cfx-B\uff082\uff0cp\uff09\uff0c\u968f\u673a\u53d8\u91cfy-B\uff083\uff0cp\uff09\uff0c\u82e5P\uff08X\u5927\u4e8e\u7b49\u4e8e1\uff09=7/16\uff0c\u5219P\uff08Y=2)=?\u968f\u673a\u53d8\u91cf\u670d\u4eceB(n, p) \u662f\u6307\uff1a \u91cd\u590d\u8bd5\u9a8cn\u6b21\uff0c\u6bcf\u6b21\u6210\u529f\u7684\u6982\u7387\u4e3ap\u3002
\u5982\u679c\u662f(2, p)\u7684\u8bdd\uff0c\u53ea\u6709\u53ef\u80fd\u51fa\u73b00,1,2, \u8fd9\u4e09\u79cd\u60c5\u51b5\uff0c\u4f60\u505a\u4e86\u4e24\u6b21\u8bd5\u9a8c\uff0c\u6700\u5927\u53ea\u80fd\u4e3a2\u3002
(3, p) \u5c31\u662f0,1,2,3, \u6700\u5927\u53ea\u80fd\u4e3a3\u3002
\u2235\u968f\u673a\u53d8\u91cf\u670d\u4eceX\uff5eB\uff082\uff0cP\uff09\uff0c\u2234P\uff08X\u22651\uff09=1-P\uff08X=0\uff09=1- C 02 \uff081-p\uff09 2 = 3 4 \uff0c\u89e3\u5f97p= 1 2 \uff0e\u2234P\uff08Y\u22651\uff09=1-P\uff08Y=0\uff09=1- C 33 \uff081-p\uff09 3 =1- 1 8 = 7 8 \uff0c\u6545\u7b54\u6848\u4e3a 7 8 \uff0e
∵随机变量服从X~B(2,P), ∴P(X≥1)=1-P(X=0)=1-C 2 0 (1-P) 2 =
∴1-P=
∴P=
∴P(Y=2)=
故答案为:
|
绛旓細鈭闅忔満鍙橀噺鏈嶄粠X锝濨锛2锛孭锛锛屸埓P锛X鈮1锛=1-P锛圶=0锛=1-C 2 0 锛1-P锛 2 = 7 16 锛屸埓1-P= 3 4 鈭碢= 1 4 鈭碢锛圷=2锛= C 23 ( 1 4 ) 2 脳 3 4 = 9 64 鏁呯瓟妗堜负锛 9 64 ...
绛旓細绠鍗曡绠椾竴涓嬪嵆鍙紝绛旀濡傚浘鎵绀
绛旓細鎰忔濇槸锛歑閬靛惊浜岄」鍒嗗竷锛岃瘯楠屾鏁颁负2锛鍗曟姒傜巼p銆備簩椤瑰垎甯冩槸鐢变集鍔埄鎻愬嚭鐨勬蹇碉紝鎸囩殑鏄噸澶峮娆$嫭绔嬬殑浼姫鍒╄瘯楠屻傚湪姣忔璇曢獙涓彧鏈変袱绉嶅彲鑳界殑缁撴灉锛岃屼笖涓ょ缁撴灉鍙戠敓涓庡惁浜掔浉瀵圭珛锛屽苟涓旂浉浜掔嫭绔嬶紝涓庡叾瀹冨悇娆¤瘯楠岀粨鏋滄棤鍏筹紝浜嬩欢鍙戠敓涓庡惁鐨勬鐜囧湪姣忎竴娆$嫭绔嬭瘯楠屼腑閮戒繚鎸佷笉鍙樸闅忔満鍙橀噺X鏈嶄粠浜岄」鍒嗗竷锛岃涓...
绛旓細鈭磒=1/3 鈭碢{Y鈮1}=1-P{Y=0}=1-(1-p)³=1-(1-1/3)³=19/27 鎴 P(X鈮1)=1-P(X=0)=1-C(2 0)*(p^0)(1-p)^2=1-(1-p)^2=3/4 p=1/2 p(y鈮1)=1-P(Y=0)=1-C(3 0)*(p^0)(1-p)^3=7/8 杩炵画鍨 杩炵画鍨嬶紙continuous锛闅忔満鍙橀噺鍗冲湪涓瀹...
绛旓細璁鹃殢鏈哄彉閲廥鏈嶄粠浜岄」鍒嗗竷b锛2锛宲锛锛岄殢鏈哄彉閲廦鏈嶄粠浜椤瑰垎甯僢锛4锛宲锛夛紝鑻P锛X鈮1锛夛紳5锛9锛屽垯P锛圷鈮1锛夛紳65锛81銆傚洜涓篜锛圶鈮1锛夛紳5锛9锛屾墍浠ユ弧瓒崇瓑寮廝锛圶鈮1锛夛紳1锛峆锛圶锛0锛夛紳1锛嶏紙1锛峱锛夛季2锛5锛9銆傚寲绠鍙緱P锛1锛3銆傛墍浠ワ紝P锛圷鈮1锛夛紳1锛峆锛圷锛0锛夛紳1锛嶏紙1锛峱锛夛季4...
绛旓細闅忔満鍙橀噺X鏈嶄粠浜岄」鍒嗗竷.鍏跺垎甯冨垪涓猴細X 0 1 2 P (1-p)² p(1-p) p²P(x=0)=(1-p)²P(X=1)=C(2,1)P(1-p)P(X=2)=p².EX=np=2p.DX=np(1-p)=2p(1-p).
绛旓細璁鹃殢鏈哄彉閲廥鏈嶄粠浜岄」鍒嗗竷b锛2锛宲锛锛岄殢鏈哄彉閲廦鏈嶄粠浜椤瑰垎甯僢锛4锛宲锛夛紝鑻P锛X鈮1锛夛紳5锛9锛屽垯P锛圷鈮1锛夛紳65锛81銆傚洜涓篜锛圶鈮1锛夛紳5锛9锛屾墍浠ユ弧瓒崇瓑寮廝锛圶鈮1锛夛紳1锛峆锛圶锛0锛夛紳1锛嶏紙1锛峱锛夛季2锛5锛9銆傚寲绠鍙緱P锛1锛3銆傛墍浠ワ紝P锛圷鈮1锛夛紳1锛峆锛圷锛0锛夛紳1锛嶏紙1锛峱锛夛季4...
绛旓細闅忔満鍙橀噺X鏈嶄粠浜岄」鍒嗗竷.鍏跺垎甯冨垪涓猴細X 0 1 2 P (1-p)² p(1-p) p²P(x=0)=(1-p)²P(X=1)=C(2,1)P(1-p)P(X=2)=p².EX=np=2p.DX=np(1-p)=2p(1-p).
绛旓細绠鍗曡绠椾竴涓嬪嵆鍙紝绛旀濡傚浘鎵绀
绛旓細绛旀鏄1/3锛屽埄鐢ㄤ簩椤瑰垎甯冨叕寮忓鍥捐绠椼傝閲囩撼锛岃阿璋紒