The following data are representative of those reported in an article on nitrogen emissions, with  x  = burner area release rate (MBtu/hr-ft  ²  ) and  y = _NOx  emission rate   (ppm):

X	100	125	125	150	150	200	200	250	250	300	300	350	400	400
y	150	140	180	210	200	310	280	400	420	440	390	590	610	680

(a) Assuming that the simple linear regression model is valid, obtain the least squares estimate of the true regression line. (Round all numerical values to four decimal places.)
y  = ??? _{(b) What is the estimate of the expected NOx}

emission rate   when the burner area release rate is equal to 220? (Round your answer to two decimal places.)

 

(c) Estimate the amount by which you expect the NO  _x emission rate to change  when the burner area release rate is reduced by 60 . (Round your answer to two decimal places.)