Daily air quality is measured by the air quality index (AQI) reported by the Environmental Protection Agency. This index reports the pollution level and what associated health effects might be a concern. The index is calculated for five major air pollutants regulated by the Clean Air Act and takes values from 0 to 300, where a higher value indicates lower air quality. AQI was reported for a sample of 91 days in 2011 in Durham, NC. The relative frequency histogram below shows the distribution of the AQI values on these days. 0.20 0.12 0.10 0.08 0.08 0.08 0.08 0.08 0.07 0.06 0.04 0.04- 0.00 10 20 30 40 50 70 daily AQI value a) Estimate the median AQI value of this sample. Median = b) Estimate Q1, Q3, and IQR for this distribution. Q1 = Q3 IQR = 0.15 0.10 0.05 50.06 0.05 0.06 60
