The following 12 data pairs relate variable x_i, the amount of fertilizer, to variable Y_i, the amount of wheatharvested:

x: 30 30 30 50 50 50 70 70 70 90 90 90

Y: 9 11 14 12 14 23 19 22 31 29 33 35

such that :

x = 720y= 252 , xy =17240,x²=49200,y²=6228

a)Find equation of linear regression line:Y = A + BX. b) 95% 2 sided confidence interval for B. c) Is there regression on input variable? d) Find 2-sided 99% prediction interval for response if x₀= 40. e) Calculate R², explain its meaning.