Chap 16 (Class Activity) Stem-and-Leaf Diagrams - Our Worst Haze Days

Reference: Worksheet 4 (p2) Constructing a Stem-and-Leaf Diagram...

Because of Singapore's geographical location, we are impacted by smoke haze when there are forest fires in the region and the prevailing southwest monsoon winds blow the smoke from the fires in our direction, which usually occur in the period of May to October.

In the past 10 years, Singapore has experienced several "worst" haze days.

Let's complete the back-to-back stem-and-leaf diagram that shows the PSI (Pollutant Standards Index) values of the two such instances in the decade and make a comparison of these 2 haziest periods.

The PSI values of 2006 October is shown in the table below (left).

Comment on the Median PSI value in 2006 October.

Are you able to tell the mean and mode from the stem-and-leaf diagram?

Now, visit the NEA website to find out what the PSI value of the days in June 2010.

Complete the table in the worksheet, and make a comparison between the 2 sets of data.

• http://app2.nea.gov.sg/psimonthly.aspx

What are your observations?