I need help with the second part

X) 2.4.88 Question A magazine published a study on the ammonia levels near the exit ramp of a highway tunnel. The data in the table below represent daily ammonia concentrations (in parts per million) on eight randomly selected days d afternoon drive time. Complete parts a through c 1 54 1.51 1.37 1 52 1 58 1 44 1.43 147 2 a. Find the range of the ammonia levels. Give the units of measurement for the range. The range is 0 21 ppm (Type an integer or a decimal ) b. Find the variance of the ammonia levels, If possible, give the units of measurement for the variance The variance is with (Round to four decimal places as needed )