Question

Simple Regression in Class Example StudentID Exam Score 10 Hours Studied 100 25 225 7 2 0 0 20 ol 75 30 25 85 80 90 65 75 95 100 9 001 002 003 004 005 006 007 008 009 010 N=10 5 15 -10 ol 20 -10 S 10 2 6 8 3 S - 3 1 3 0 0 400 9 60 -2 4 100 25 -S 2 -3 9 65 70 55 70 Mean=75 20 ISI ol 13 -20 400 C 0 $ 2 - 9 25 Mean-5 11400 E 70 ΙΣ 235 Variance (s): s? Standard Deviation (s): SV S. Sy Covariance: -Xv >> Correlation (r): Cov(x,y) (5)) =

Answer 1

Given from the table: =75, 7-5, E(X;-)=0, ZX; -7)=70, n=10. E(:-7)=0, E(Y:-7)=1400, E (x; -X)*(71-5)=235 Variance (s) = (x-x) - 363-8). 7. = 7 E(Y: -72 _ 1400 70 = 7 n 10 х n = 140. 10 Sy

Standard Deviation(s): S = √² = J7 = 2.646 Sx = √5 / = =2.646, Sy = usy = $140=11.832

Covariance: 235=23.5 10 n Cov(x,y) = E6-7)(-5) 23.5 3:31 = 0.7505 Correlation () COV(x,y) (Sulsy) 23.5 (2.646+(11832) 0.751 ro

Simple Regression 235= 3.357 70 b= -246.78 = -246 78+(3:35+)** * As number of hours studied goes up by ! Exam score goes up by 5. ZK-5) [y; - ) (x;-) a-y-bă = 5-(3-357)* (15) = -246.775 Y = atbx