ÌâÄ¿ÄÚÈÝ

¶ÔijУ¸ß¶þÄ꼶ѧÉú²Î¼ÓÉçÇø·þÎñ´ÎÊý½øÐÐͳ¼Æ£¬Ëæ»ú³éÈ¡NÃûѧÉú×÷ΪÑù±¾£¬µÃµ½ÕâNÃûѧÉú²Î¼ÓÉçÇø·þÎñµÄ´ÎÊý£®¸ù¾Ý´ËÊý¾Ý×÷³öÁËƵÊýÓëƵÂʵÄͳ¼Æ±íºÍƵÂÊ·Ö²¼Ö±·½Í¼ÈçÏ£º
·Ö×é ƵÊý ƵÂÊ
[3£¬6£© 10 m
[6£¬9£© n p
[9£¬12£© 4 q
[12£¬15] 2 0.05
ºÏ¼Æ N 1
£¨1£©Çó³ö±íÖÐN£¬p¼°Í¼ÖÐaµÄÖµ£»
£¨2£©ÔÚËùÈ¡Ñù±¾ÖУ¬´Ó²Î¼ÓÉçÇø·þÎñµÄ´ÎÊý²»ÉÙÓÚ9´ÎµÄѧÉúÖÐÈÎÑ¡2ÈË£¬ÇóÖÁÉÙÓÐÒ»È˲μÓÉçÇø·þÎñ´ÎÊýÔÚÇø¼ä[12£¬15]ÄڵĸÅÂÊ£®
·ÖÎö£º£¨1£©ÓÉ·Ö×é[12£¬15£©ÄÚµÄƵÊýÊÇ2£¬ÆµÂÊÊÇ0.05£¬¿ÉµÃ
2
N
=0.05
£¬ËùÒÔN=40£®ÔÙÓÉ10+n+4+2=40£¬½âµÃn=24£¬ÓÉ´ËÇóµÃp=
n
N
ÒÔ¼°a=
p
3
µÄÖµ£®
£¨2£©¼Ç¡°ÖÁÉÙÓÐÒ»È˲μÓÉçÇø·þÎñ´ÎÊýÔÚÇø¼ä[12£¬15£©ÄÚ¡±ÎªÊ¼þA£®Õâ¸öÑù±¾ÖвμÓÉçÇø·þÎñ´ÎÊý²»ÉÙÓÚ9´ÎµÄѧÉú¹²ÓÐ4+2=6ÈË£®´ÓÕâ6ÈËÖÐÈÎÑ¡2È˵ÄËùÓпÉÄܽá¹û£¬ÓÃÁоٷ¨ÇóµÃ¹²15ÖÖ£¬Ê¼þA°üº¬µÄ½á¹ûÓÐ9ÖÖ£¬ÓÉ´ËÇóµÃʼþA·¢ÉúµÄ¸ÅÂÊ£®
½â´ð£º½â£º£¨1£©ÓÉ·Ö×é[12£¬15£©ÄÚµÄƵÊýÊÇ2£¬ÆµÂÊÊÇ0.05£¬¿ÉµÃ
2
N
=0.05
£¬ËùÒÔN=40£®
ÒòΪƵÊýÖ®ºÍΪ40£¬ËùÒÔ10+n+4+2=40£¬½âµÃn=24£®
ËùÒÔ£¬p=
n
N
=
24
40
=0.6
£®
ÒòΪaÊǶÔÓ¦·Ö×é[6£¬9£©µÄƵÂÊÓë×é¾àµÄÉÌ£¬ËùÒÔ£¬a=
p
3
=
0.6
3
=0.2
£®
£¨2£©¼Ç¡°ÖÁÉÙÓÐÒ»È˲μÓÉçÇø·þÎñ´ÎÊýÔÚÇø¼ä[12£¬15£©ÄÚ¡±ÎªÊ¼þA£®
Õâ¸öÑù±¾ÖвμÓÉçÇø·þÎñ´ÎÊý²»ÉÙÓÚ9´ÎµÄѧÉú¹²ÓÐ4+2=6ÈË£®
¼ÇÔÚÇø¼ä[9£¬12£©ÄÚµÄ4ÈËΪa1£¬a2£¬a3£¬a4£¬ÔÚÇø¼ä[12£¬15£©ÄÚµÄ2ÈËΪb1£¬b2£®
´ÓÕâ6ÈËÖÐÈÎÑ¡2È˵ÄËùÓпÉÄܽá¹ûÓУº{a1£¬a2}£¬{a1£¬a3}£¬{a1£¬a4}£¬{a1£¬b1}£¬{a1£¬b2}£¬{a2£¬a3}£¬{a2£¬a4}£¬{a2£¬b1}£¬
{a2£¬b2}£¬{a3£¬a4}£¬{a3£¬b1}£¬{a3£¬b2}£¬{a4£¬b1}£¬{a4£¬b2}£¬{b1£¬b2}£¬¹²15ÖÖ£®
ʼþA°üº¬µÄ½á¹ûÓУº{a1£¬b1}£¬{a1£¬b2}£¬{a2£¬b1}£¬{a2£¬b2}£¬{a3£¬b1}£¬{a3£¬b2}£¬{a4£¬b1}£¬{a4£¬b2}£¬{b1£¬b2}£¬¹²9ÖÖ£®
ËùÒÔËùÇó¸ÅÂÊΪP(A)=
9
15
=
3
5
=0.6
£®
µãÆÀ£º±¾Ð¡ÌâÖ÷Òª¿¼²éƵÊý¡¢ÆµÂʵȻù±¾¸ÅÄ¿¼²é¹Åµä¸ÅÐ͵Ȼù´¡ÖªÊ¶£¬ÊôÓÚ»ù´¡Ì⣮
Á·Ï°²áϵÁдð°¸
Ïà¹ØÌâÄ¿

Î¥·¨ºÍ²»Á¼ÐÅÏ¢¾Ù±¨µç»°£º027-86699610 ¾Ù±¨ÓÊÏ䣺58377363@163.com

¾«Ó¢¼Ò½ÌÍø