Question

19£®Í¼ÎªÄ³¼Ò×åµÄÒÅ´«ÏµÆ×ͼ£¬¼×¡¢ÒÒÊÇÁ½ÖÖÒÅ´«·½Ê½²»Í¬µÄÒÅ´«²¡£¬Óë¼×²¡Ïà¹ØµÄ»ùÒòΪB¡¢b£¬ÓëÒÒ²¡Ïà¹ØµÄ»ùÒòΪD¡¢d£®¾Ýͼ»Ø´ðÏÂÁÐÎÊÌ⣺

£¨1£©¼×²¡µÄÒÅ´«·½Ê½ÊÇ°éXȾɫÌåÏÔÐÔÒÅ´«£¬ÒÒ²¡µÄÒÅ´«·½Ê½Êdz£È¾É«ÌåÏÔÐÔÒÅ´«£®
£¨2£©¢ò₅µÄ»ùÒòÐÍΪDdX^bY£¬¢ó₂Ϊ´¿ºÏ×ӵĸÅÂÊΪ$\frac{1}{2}$£®
£¨3£©Èô¢ó₄Óë¢ó₅»éÅ䣬Æäºó´ú»¼²¡µÄ¸ÅÂÊΪ$\frac{1}{2}$£®
£¨4£©ÒÑ֪ijµØÇøÈËȺÖлùÒòdµÄƵÂÊΪ90%£¬¢ó₆ºÍ¸ÃµØÇø±íÏÖÐÍÓëÆäÏàͬµÄһŮ×Ó»éÅ䣬ÔòËûÃÇÉúÏÂÕý³£º¢×ӵĸÅÂÊΪ$\frac{3}{19}$£®

Answer 1

·ÖÎö ¢ò-1ºÍ¢ò-2¶¼»¼¼×²¡£¬Æä¶ù×Ó¢ó-1²»»¼¼×²¡£¬¹Ê¼×²¡ÎªÏÔÐÔÒÅ´«²¡£¬ÓÖÒòΪÄл¼ÕßµÄĸÇ׺ÍÅ®¶ù¶¼Îª»¼Õߣ¬¹Ê¼×²¡Îª°éXÏÔÐÔÒÅ´«²¡£»¢ò-5ºÍ¢ò-6¶¼»¼ÒÒ²¡£¬ÆäÅ®¶ù¢ó-5Õý³££¬¹ÊÒÒ²¡Îª³£È¾É«ÌåÏÔÐÔÒÅ´«£¬¾Ý´Ë´ðÌ⣮

½â´ð ½â£º£¨1£©¸ù¾Ý¶Ô¼Ò×åµÄÒÅ´«ÏµÆ×ͼ·ÖÎö£¬¼×²¡Îª°éXȾɫÌåÏÔÐÔÒÅ´«£¬ÒÒ²¡µÄÒÅ´«·½Ê½Êdz£È¾É«ÌåÏÔÐÔÒÅ´«£®
£¨2£©¢ò₅µÄ»¼ÒÒ²¡£¬µ«ÊÇÅ®¶ùÕý³££¬²»»¼¼×²¡£¬Æä»ùÒòÐÍΪDdX^bY£¬¢ó₂»¼¼×²¡£¬¸ç¸ç¢ó-1²»»¼¼×²¡£¬¢ó₂¹ØÓڼײ¡»ùÒòÐͼ°¸ÅÂÊΪ$\frac{1}{2}$X^BX^B¡¢$\frac{1}{2}$X^BX^b£¬¢ó₂²»»¼ÒÒ²¡»ùÒòÐÍΪdd£¬¹Ê¢ó₂Ϊ´¿ºÏ×ӵĸÅÂÊΪ$\frac{1}{2}$£®
£¨3£©¢ó₄»¼¼×²¡²»»¼ÒÒ²¡£¬»ùÒòÐÍΪddX^BY£¬¢ó₅Õý³££¬»ùÒòÐÍΪddX^bX^b£¬Èô¢ó₄Óë¢ó₅»éÅ䣬Æäºó´ú»¼²¡µÄ¸ÅÂÊΪ$\frac{1}{2}$£®
£¨4£©£©¢ó₆µÄ»ùÒòÐͼ°¸ÅÂÊΪ$\frac{1}{3}$DDX^bY¡¢$\frac{2}{3}$DdX^bY£¬ÒÑ֪ijµØÇøÈËȺÖлùÒòdµÄƵÂÊΪ90%£¬ÔòDµÄ»ùÒòƵÂÊΪ10%£¬¸ù¾ÝÒÅ´«Æ½ºâ¶¨ÂÉ£¬DDµÄ»ùÒòÐÍƵÂÊΪ10%¡Á10%=0.01£¬DdµÄ»ùÒòÐÍƵÂÊΪ2¡Á10%¡Á90%=0.18£¬Òò´Ë»¼ÒÒ²¡µÄÈËDdµÄ¸ÅÂÊΪ$\frac{0.18}{0.01+0.18}$=$\frac{18}{19}$£¬¸ÃµØÇø±íÏÖÐÍÓë¢ó₅ÏàͬµÄһŮ×ӵĻùÒòÐͼ°¸ÅÂÊΪ$\frac{1}{19}$DDX^bX^b¡¢$\frac{18}{19}$DdX^bX^b£¬ÔòËûÃÇÉúÏÂÕý³£º¢×ӵĸÅÂÊΪ$\frac{2}{3}$¡Á$\frac{18}{19}$¡Á$\frac{1}{4}$=$\frac{3}{19}$£®
¹Ê´ð°¸Îª£º
£¨1£©°éXȾɫÌåÏÔÐÔÒÅ´«     ³£È¾É«ÌåÏÔÐÔÒÅ´«    
£¨2£©DdX^bY    $\frac{1}{2}$
£¨3£©$\frac{1}{2}$           
£¨4£©$\frac{3}{19}$

µãÆÀ ±¾Ìâ½áºÏϵÆ×ͼ£¬¿¼²é³£¼ûµÄÈËÀàÒÅ´«²¡£¬ÒªÇó¿¼ÉúÕÆÎÕÈËÀàÒÅ´«²¡µÄÒÅ´«Ìص㣬ÄÜÀûÓÿھ÷²¢½áºÏÌâ¸ÉÐÅÏ¢ÅжÏϵÆ×ͼÖÐÁ½ÖÖÒÅ´«²¡µÄÒÅ´«·½Ê½£¬½ø¶øÍƶÏÏàÓ¦¸öÌåµÄ»ùÒòÐÍ£¬Í¬Ê±ÄÜÀûÓÃÖð¶Ô·ÖÎö½øÐÐÏà¹Ø¸ÅÂʵļÆË㣮