Question

Let X be the number of matches played by the player and Y he the number of matches in which he scored more thun 50 runs. The following data is obtained for 5 players : 

No. of Matches Played (X)	Data of matches of 5 players
	21	25	26	24	19
Scored more than 50 in a match (Y)	19	20	24	21	16

Find the regression line of X on Y. 

Answer 1

x	y	`x - barx`	`y - bary`	`(x - barx)(y - bary)`	`(y - bary)^2`
21	19	-2	-1	2	1
25	20	2	0	0	0
26	24	3	4	12	16
24	21	1	1	1	1
19	16	-4	-4	16	16
115	100			31	34

`barx = (Σx)/n = 115/5 = 23`

and `bary = (Σy)/n = 100/5 = 20`

Regression coefficient of x on y, 

`b_(xy) = (Σ(x - barx)(y - bary))/(Σ(y - bary)^2) = 31/34`

 = `31/34`

Equation of regression line of x on y is 

`(x - barx) = b_(xy)(y - bary)`

`(x - 23) = 31/34(y - 20)`

x - 23 = 0.91(y - 20)

x - 23 = 0.91y - 18.2

x = 0.91y + 4.8