. Question 13 Next QuestionQuestion 12 A researcher for the EPA measured the amount of arsenic in the water near a sewage treatment plant. Over 12 days, he took n = 40 measurements (in ppb). His sample data is summarized in the frequency distribution polygon shown below. O 20 25 50 35 40 45 50 55 60 65 70 Arsenic (ppb) How many measurements taken in this time frame were less than 55 ppb? ans =O Question 6 The following is the beginning of a frequency table Class Frequency 60 - 69 2 70 - 79 4 Find the upper class boundary for the second given class. What is the class width? 9 What would be the class midpoint of the next class (in other words, if a third class is added after the existing 2)? > Next