I just need part a

(1 point) Keeping water supplies clean requires regular measurement of levels of pollutants. To calibrate such measurements, the laboratory measures known standard solutions and uses regression to relate absorbence and pollutant concentration. Here is one series of data on the absorbence for different levels of nitrates. Nitrates are measured in milligrams per liter of water. Nitrates 50 75 125 250 250 600 800 1300 1600 2000 Absorbance 6.17.4 14.7 24.9 40.1 94.7 145.5 197 228.9 233.2 Chemical theory says that these data should lie on a straight line. If the correlation is not at least 0.997, something went wrong and the calibration procedure is repeated. (a) Find the correlation r. r = (b) Must the calibration be done again? (Answer YES or NO). ANSWER: yes