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XÉèXµÄ·Ö²¼ÂÉΪP012,Æä·Ö²¼º¯ÊýF(x),Ôò0.30.50.2F(1.5)____.

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1¡¢ÒÑÖªP(A)?0.5, P(AB)?0.2, P(B)?0.4, Çó

(1) P(AB); (2) P(A?B); (3) P(A?B); (4) P(AB).

½â (1) ÒòΪAB?AB?B, ÇÒABÓëABÊDz»ÏàÈݵÄ, ¹ÊÓÐP(AB)?P(AB)?P(B) ÓÚÊÇP(AB)?P(B)?P(AB)?0.4?0.2?0.2;

(2) P(A)?1?P(A)?1?0.5?0.5,

P(A?B)?P(A)?P(AB)?0.5?0.2?0.3;

(3) P(A?B)?p(A)?P(B)?P(AB)?0.5?0.4?0.2?0.7;

(4) P(AB)?P(A?B)?1?P(A?B)?1?0.7?0.3.

2¡¢Ä³³ÇÊÐÖз¢ÐÐ2ÖÖ±¨Ö½A, B. ¾­µ÷²é, ÔÚÕâ2ÖÖ±¨Ö½µÄ¶©»§ÖÐ, ¶©ÔÄA±¨µÄÓÐ45%,¶©ÔÄB±¨µÄÓÐ35%, ͬʱ¶©ÔÄ2ÖÖ±¨Ö½A, BµÄÓÐ10%. ÇóÖ»¶©Ò»ÖÖ±¨Ö½µÄ¸ÅÂÊa.£¨

½â ¼ÇÊÂA?{¶©ÔÄA±¨},B?{¶©ÔÄB±¨}, Ôò

{Ö»¶©Ò»ÖÖ±¨}?(A?B)?(B?A)?AB?BA,

ÓÖÕâÁ½¼þÊÂÊÇ»¥²»ÏàÈݵÄ, ÓɸÅÂʼӷ¨¹«Ê½¼°ÐÔÖÊ4, ÓÐ

??P(A?AB)?P(B?AB)?P(A)?P(AB)?P(B)?P(AB)?0.45?0.1?0.35?0.1=0.6. 3¡¢½«±êºÅΪ1, 2, 3, 4µÄËĸöÇòËæÒâµØÅųÉÒ»ÐÐ, ÇóÏÂÁи÷ʼþµÄ¸ÅÂÊ:

(1) ¸÷Çò×Ô×óÖÁÓÒ»ò×ÔÓÒÖÁ×óÇ¡ºÃÅųÉ1, 2, 3, 4µÄ˳Ðò; (2) µÚ1ºÅÇòÅÅÔÚ×îÓұ߻ò×î×ó±ß; (3) µÚ1ºÅÇòÓëµÚ2ºÅÇòÏàÁÚ;

(4) µÚ1ºÅÇòÅÅÔÚµÚ2ºÅÇòµÄÓÒ±ß(²»Ò»¶¨ÏàÁÚ).

½â ½«4¸öÇòËæÒâµØÅųÉÒ»ÐÐÓÐ4!=24ÖÖÅÅ·¨, ¼´»ù±¾Ê¼þ×ÜÊýΪ24. ¼Ç(1), (2),(3), (4)µÄʼþ·Ö±ðΪA,B,C,D.

(1) AÖÐÓÐÁ½ÖÖÅÅ·¨,¹ÊÓÐP(A)?21?. 2412121?. 242(3) ÏȽ«µÚ1,2ºÅÇòÅÅÔÚÈÎÒâÏàÁÚÁ½¸öλÖÃ, ¹²ÓÐ2?3ÖÖÅÅ·¨, ÆäÓàÁ½¸öÇò¿ÉÔÚÆäÓàÁ½¸öλÖÃÈÎÒâÅÅ·Å, ¹²ÓÐ2! ÖÖÅÅ·¨, Òò¶øCÓÐ2?3?2?12ÖÖÅÅ·¨, ¹ÊP(C)?12/24?1/2.

(2) BÖÐÓÐ2?(3!)?12ÖÖÅÅ·¨, ¹ÊÓÐP(B)?(4) µÚ1ºÅÇòÅÅÔÚµÚ2ºÅÇòµÄÓұߵÄÿһÖÖÅÅ·¨, ½»»»µÚ1ºÅÇòºÍµÚ2ºÅÇòµÄλÖñã¶ÔÓ¦ÓÚµÚ1ºÅÇòÅÅÔÚµÚ2ºÅÇòµÄ×ó±ßµÄÒ»ÖÖÅÅ·¨, ·´Ö®ÒàÈ».

Òò¶øµÚ1ºÅÇòÅÅÔÚµÚ2ºÅÇòµÄÓÒ±ßÓëµÚ1ºÅÇòÅÅÔÚµÚ2ºÅÇòµÄ×ó±ßµÄÅÅ·¨ÖÖÊýÏàͬ, ¸÷Õ¼×ÜÅÅ·¨ÊýµÄ1/2, ¹ÊÓÐP(D)?1/2.

13

4¡¢ÉèijÅú²úÆ·ÖÐ, ¼×, ÒÒ, ±ûÈý³§Éú²úµÄ²úÆ··Ö±ðÕ¼45%, 35%, 20%, ¸÷³§µÄ²úÆ·µÄ´ÎÆ·ÂÊ·Ö±ðΪ4%, 2%, 5%, ÏÖ´ÓÖÐÈÎȡһ¼þ,

(1) ÇóÈ¡µ½µÄÊÇ´ÎÆ·µÄ¸ÅÂÊ;

(2) ¾­¼ìÑé·¢ÏÖÈ¡µ½µÄ²úƷΪ´ÎÆ·, Çó¸Ã²úÆ·ÊǼ׳§Éú²úµÄ¸ÅÂÊ.

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P(A1)?45%,P(A2)?35%,P(A3)?20%,P(B|A1)?4%,P(B|A2)?2%,P(B|A3)?5%,

(1) ÓÉÈ«¸ÅÂʹ«Ê½µÃP(B)??P(A)P(B|A)?3.5%.

iii?13(2) Óɱ´Ò¶Ë¹¹«Ê½(»òÌõ¼þ¸ÅÂʶ¨Òå), µÃ

P(A1B)P(A1)P(B|A1)P(A1|B)???51.4%.

P(B)P(B)5¡¢8Ö§²½Ç¹ÖÐÓÐ5Ö§ÒÑУ׼¹ý£¬3֧δУ׼. Ò»ÃûÉäÊÖÓÃУ׼¹ýµÄǹÉä»÷ʱ£¬ÖаеĸÅ

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½â ÉèB1?{ʹÓõÄǹУ׼¹ý}, B2?{ʹÓõÄǹδУ׼}, A?{Éä»÷ʱÖаÐ},ÔòB1,B2ÊÇ

53?µÄÒ»¸ö»®·Ö, ÇÒP(B1)?,P(B2)?,P(A|B1)?0.8,P(A|B2)?0.3.

88P(A|B1)P(B1)40Óɱ´Ò¶Ë¹¹«Ê½, µÃ P(B1|A)??.

P(A|B1)P(B1)?P(A|B2)P(B2)49ÕâÑù, ËùÓõÄǹÊÇУ׼¹ýµÄ¸ÅÂÊΪ

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5?P{175?X??}?1?P{X?17}5 P{X?17} ?1????175?170???1??(0.65)

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7¡¢ÉèijÏÈü³É¼¨X~N(65, 100)£¬Èô°´²ÎÈüÈËÊýµÄ10%·¢½±£¬ÎÊ»ñ½±·ÖÊýÏßÓ¦ ¶¨Îª¶àÉÙ£¿

½â Éè»ñ½±·ÖÊýÏßΪx0, ÔòÇóʹP{X?x0}?0.1³ÉÁ¢µÄx0.

14

?x?65?P{X?x0}?1?P{X?x0}?1?F(x0)?1???0??0.1,

10??x?65?x?65?¼´??0?1.29, ½âµÃx0?77.9, ¹Ê·ÖÊýÏ߿ɶ¨Îª78·Ö. ??0.9, ²é±íµÃ01010??8ÉèËæ»ú±äÁ¿?X,Y?µÄ¸ÅÂÊÃܶÈΪ

?Ax,0?x?1,0?y?x f?x,y???

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1x10 ?dx?Axdy?1 ¼´

A?1,A?3 31?=?2?1£¨2£©P?X?,Y??2??112dx?3xdy

03 ?9 169¡¢Ä³¹«¹²Æû³µÕ¾´ÓÉÏÎç7ʱÆð, ÿ15·ÖÖÓÀ´Ò»°à³µ, ¼´7:00, 7:15, 7:30, 7:45µÈʱ¿ÌÓÐÆû³µµ½´ï´ËÕ¾, Èç¹û³Ë¿Íµ½´ï´Ëվʱ¼äXÊÇ7:00µ½7:30Ö®¼äµÄ¾ùÔÈËæ»ú±äÁ¿,ÊÔÇóËûºò³µÊ±¼äÉÙÓÚ5·ÖÖӵĸÅÂÊ.

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³µÕ¾, ¹ÊËùÇó¸ÅÂÊΪ

P{10?X?15}?P{25?X?30}??1dx?103015?11dx? 2530330¼´³Ë¿Íºò³µÊ±¼äÉÙÓÚ5·ÖÖӵĸÅÂÊÊÇ1/3.

¡¤10¡¢Ä³Ôª¼þµÄÊÙÃüX·þ´ÓÖ¸Êý·Ö²¼, ÒÑÖªÆä²ÎÊý??1/1000, Çó3¸öÕâÑùµÄÔª¼þʹÓÃ1000Сʱ, ÖÁÉÙÒÑÓÐÒ»¸öË𻵵ĸÅÂÊ.

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x??1?e?1000,x?0F(x)??.

?0,x?0?Óɴ˵õ½

P{X?1000}?F?1000??1?e?1

15

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0,ÆäËü?Çó±ßÔµ¸ÅÂÊÃܶÈfX(x),fY(y).

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fX(x)????????f(x,y)dy?????x2x6dy?6(x?x2),0?x?1,

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0 0.1 0.2 0

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¶øP{X?0,Y??1}?0.1, ¼´P{X?0,Y??1}?P{X?0}P{Y??1} ËùÒÔ, XÓëY²»¶ÀÁ¢.

(3)F(0,0)?P{X?0,Y?0}?P{X?0,Y??1}?0.2?0.1?0.3. 13¡¢ÒÑÖªÀëÉ¢ÐÍËæ»úÏòÁ¿(X,Y)µÄ¸ÅÂÊ·Ö²¼Îª

Y ?1 X 0 0.1 0 0.2 2 0 16