The Air Quality Index (AQI) is a measure of air pollution, combining measurements of ozone, carbon monoxide, sulfur dioxide, nitrogen dioxide, airborne particles and visibility into a single index. The AQI for 420 days measured in the Illawarra region, NSW was plotted and summarised below.
Figure: Density plot of Air Quality Index for Illawarra

Figure: Box plot of Air Quality Index for Illawarra

Descriptive statistics

Which of the following statements is correct?
Note: you are not required to have any context knowledge about the air quality index, apart from knowing it can take any value from 0 and above.

Question

The Air Quality Index (AQI) is a measure of air pollution, combining measurements of ozone, carbon monoxide, sulfur dioxide, nitrogen dioxide, airborne particles and visibility into a single index. The AQI for 420 days measured in the Illawarra region, NSW was plotted and summarised below. 
 Figure: Density plot of Air Quality Index for Illawarra 
  
    
   
 Figure: Box plot of Air Quality Index for Illawarra 
  
    Descriptive statistics   
 
 Which of the following statements is correct? 
 Note: you are not required to have any context knowledge about the air quality index, apart from knowing it can take any value from 0 and above.

Accepted Answer

AQI is positively skewed, so the distribution is best summarised using the median (50) and the interquartile range (38 to 76).

Answer

AQI has outliers which must be removed before any summary statistics are calculated.

Answer

AQI is negatively skewed, so the distribution is best summarised using the median (50) and the range (23 to 1398).

Answer

AQI is Normally distributed, so the distribution is best summarised using the mean (88) and the standard deviation (139.2).

Crowdly

The Air Quality Index (AQI) is a measure of air pollution, combining measurement...

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