已知两组数x1,x2······,xn和y1,y2,······,yn它们的平均数分别是A,B,求下列各组数的平均数:(1)x1-y1,x2-y2······xn-yn:(2)x1,y1,x2,y2,······xn,yn.
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![已知两组数x1,x2······,xn和y1,y2,······,yn它们的平均数分别是A,B,求下列各组数的平均数:(1)x1-y1,x2-y2······xn-yn:(2)x1,y1,x2,y2,······xn,yn.](/uploads/image/z/14332670-62-0.jpg?t=%E5%B7%B2%E7%9F%A5%E4%B8%A4%E7%BB%84%E6%95%B0x1%2Cx2%C2%B7%C2%B7%C2%B7%C2%B7%C2%B7%C2%B7%2Cxn%E5%92%8Cy1%2Cy2%2C%C2%B7%C2%B7%C2%B7%C2%B7%C2%B7%C2%B7%2Cyn%E5%AE%83%E4%BB%AC%E7%9A%84%E5%B9%B3%E5%9D%87%E6%95%B0%E5%88%86%E5%88%AB%E6%98%AFA%2CB%2C%E6%B1%82%E4%B8%8B%E5%88%97%E5%90%84%E7%BB%84%E6%95%B0%E7%9A%84%E5%B9%B3%E5%9D%87%E6%95%B0%EF%BC%9A%EF%BC%881%EF%BC%89x1-y1%2Cx2-y2%C2%B7%C2%B7%C2%B7%C2%B7%C2%B7%C2%B7xn-yn%EF%BC%9A%EF%BC%882%EF%BC%89x1%2Cy1%2Cx2%2Cy2%2C%C2%B7%C2%B7%C2%B7%C2%B7%C2%B7%C2%B7xn%2Cyn.)
已知两组数x1,x2······,xn和y1,y2,······,yn它们的平均数分别是A,B,求下列各组数的平均数:(1)x1-y1,x2-y2······xn-yn:(2)x1,y1,x2,y2,······xn,yn.
已知两组数x1,x2······,xn和y1,y2,······,yn它们的平均数分别是A,B,求下列各组数的平均数:
(1)x1-y1,x2-y2······xn-yn:
(2)x1,y1,x2,y2,······xn,yn.
已知两组数x1,x2······,xn和y1,y2,······,yn它们的平均数分别是A,B,求下列各组数的平均数:(1)x1-y1,x2-y2······xn-yn:(2)x1,y1,x2,y2,······xn,yn.
1.(x1-y1+x2-y2······xn-yn)/n=(x1+x2······+xn)/n-(y1+y2+······+yn)/n=A-B
2.(x1+y1+x2+y2,······xn+yn)/2n=(x1+x2······+xn)/2n+(y1+y2+······+yn)/2n=(A+B)/2
A-B
A/2+B/2 除以2n
1,全加在一起,除以n,等于A-B
2、全加在一起,除以n,等于A+B
A=(x1+x2+···+xn)/n
B=(y1+y2+···+yn)/n
( x1-y1+x2-y2+···+xn-yn)/n
=[(x1+x2+···+xn)-(y1+y2+···+yn)]/n
=(x1+x2+···+xn)/n - (y1+y2+···+yn)/n
=A-B
( x1+y1+x2+y2+···+xn+yn)/n
=[(x1+x2+···+xn)+(y1+y2+···+yn)]/n
=(x1+x2+···+xn)/n + (y1+y2+···+yn)/n
=A+B