Question

27¡¢ÔÚ±¾Ñ§ÆÚij´Î¿¼ÊÔÖУ¬Ä³Ð£³õ¶þ£¨1£©¡¢³õ¶þ£¨2£©Á½°àѧÉúÊýѧ³É¼¨Í³¼ÆÈçÏÂ±í£º

·ÖÊý		50	60	70	80	90	100
ÈËÊý	¶þ£¨1£©°à	3	5	16	3	11	12
	¶þ£¨2£©°à	2	5	11	12	13	7

Çë¸ù¾Ý±í¸ñÌṩµÄÐÅÏ¢»Ø´ðÏÂÁÐÎÊÌ⣺
£¨1£©¶þ£¨1£©°àƽ¾ù³É¼¨Îª

80

·Ö£¬¶þ£¨2£©°àƽ¾ù³É¼¨Îª

80

·Ö£¬´Óƽ¾ù³É¼¨¿´Á½¸ö°à³É¼¨Ë­ÓÅË­´Î£¿
£¨2£©¶þ£¨1£©°àÖÚÊýΪ

70

·Ö£¬¶þ£¨2£©°àÖÚÊýΪ

90

·Ö£®´ÓÖÚÊý¿´Á½¸ö°àµÄ³É¼¨Ë­ÓÅË­´Î£¿

¶þ£¨2£©°à

£®
£¨3£©ÒÑÖª¶þ£¨1£©°àµÄ·½²î´óÓÚ¶þ£¨2£©°àµÄ·½²î£¬ÄÇô˵Ã÷ʲô£¿

Answer 1

·ÖÎö£º£¨1£©¸ù¾Ý¼ÓȨƽ¾ùÊýµÄÒâÒåÖ±½Ó¼ÆËã¼´¿É½â´ð£®
£¨2£©¸ù¾ÝÒ»×éÊý¾ÝÖгöÏÖ´ÎÊý×î¶àµÄÊý¾Ý½Ð×öÖÚÊý½â´ð¼´¿É£®
£¨3£©¸ù¾Ý·½²îµÄÒâÒå½â´ð¼´¿É£®

½â´ð£º½â£º£¨1£©Ò»°à£¨50¡Á3+60¡Á5+70¡Á16+80¡Á3+90¡Á11+100¡Á12£©¡Â£¨3+5+16+3+11+12£©
=80·Ö£»
¶þ°à£¨50¡Á2+60¡Á5+70¡Á11+80¡Á12+90¡Á13+100¡Á7£©¡Â£¨2+5+11+12+13+7£©
=80·Ö£»
Ò»Ñù£®
£¨2£©Ò»°àÖÚÊýΪ70·Ö£»
¶þ°àÖÚÊýΪ90·Ö£»
¶þ£¨2£©°à³É¼¨ÓÅ£®
£¨3£©¶þ£¨1£©°àµÄ·½²î´óÓÚ¶þ£¨2£©°àµÄ·½²î£¬ËµÃ÷¶þ£¨1£©°àµÄѧÉú³É¼¨²»ºÜÎȶ¨£¬²¨¶¯½Ï´ó£®

µãÆÀ£º±¾Ì⿼²éƽ¾ùÊý¡¢ÖÚÊýÒÔ¼°·½²îµÄÒâÒ壮¼ÓȨƽ¾ùÊý£ºÈôn¸öÊýx₁£¬x₂£¬x₃£¬¡­£¬x_nµÄȨ·Ö±ðÊÇw₁£¬w₂£¬w₃£¬¡­£¬w_n£¬Ôò$frac{{x}_{1}{w}_{1}+{x}_{2}{w}_{2}+¡­+{x}_{n}{w}_{n}}{{w}_{1}+{w}_{2}+¡­+{w}_{n}}$½Ð×öÕân¸öÊýµÄ¼ÓȨƽ¾ùÊý£®Ò»×éÊý¾ÝÖгöÏÖ´ÎÊý×î¶àµÄÊý¾Ý½Ð×öÖÚÊý£®·½²îÊÇÓÃÀ´ºâÁ¿Ò»×éÊý¾Ý²¨¶¯´óСµÄÁ¿£¬·½²îÔ½´ó£¬±íÃ÷Õâ×éÊý¾ÝÆ«Àëƽ¾ùÊýÔ½´ó£¬¼´²¨¶¯Ô½´ó£¬Êý¾ÝÔ½²»Îȶ¨£»·´Ö®£¬·½²îԽС£¬±íÃ÷Õâ×éÊý¾Ý·Ö²¼±È½Ï¼¯ÖУ¬¸÷Êý¾ÝÆ«Àëƽ¾ùÊýԽС£¬¼´²¨¶¯Ô½Ð¡£¬Êý¾ÝÔ½Îȶ¨£®