Coal ges is produced oto peswerks. Polutonts in the ges are removed by serubbers, which beceme less end less efficient as time goes on. The following mesuremerts, made at the stert of each month, show the rete at wtech pallutants ere scaping in tanmanth)in the g: O12 34s6 Rate psilutants escsoe 689 11 14 17 21 Time (nonths (a) Meke an averestimate and an underestimate of the total quentity of polutents thet esceped during the Frst month. n overestimane is cons. An underestinate is Dons LI TO TERT (b) Make an oeerestimete and an underentimate of the tatal quentity of polutenta thet esceped during the sx mantha. n overestimate is tons. An underesmateis bons