血球体积x/mm | 45 | 42 | 46 | 48 | 42 | 35 | 58 | 40 | 39 | 50 |
红血球数y/百万 | 6.53 | 6.30 | 9.52 | 7.50 | 6.99 | 5.90 | 9.49 | 6.20 | 6.55 | 8.72 |
(1)画出散点图;
(2)求回归直线方程.
血球体积x/mm | 45 | 42 | 46 | 48 | 42 | 35 | 58 | 40 | 39 | 50 |
红血球数y/百万 | 6.53 | 6.30 | 9.52 | 7.50 | 6.99 | 5.90 | 9.49 | 6.20 | 6.55 | 8.72 |
(1)画出散点图;
(2)求回归直线方程.
达到最小值,其中a、b是任意直线的斜率和截距.解
:(1)散点图如下:
(2)
=
(45+42+46+48+42+35+58+40+39+50)=44.50,
=
(6.53+6.30+9.52+7.50+6.99+5.90+9.49+6.20+6.55+8.72)=7.37,
设回归直线的方程为
=a
+b,则
a=
=0.175,b=
-a
=-0.42,
所以所求的回归直线为
=0.175x-0.42.