1. Lesson 2

1.3. Explore 2

Mathematics 30-3 Module 4

Module 4: Statistics

 

This photograph is of houses built up the side of a hill in Vancouver.

Hemera/Thinkstock

As you completed Self-Check 1, you may have noticed that Vancouver’s average housing price greatly influenced the mean, causing Canada’s average housing cost to be higher. However, it may have had little influence on the median.

 

Vancouver’s data is an example of an outlier. As you learned in Module 3, an outlier is a data point that is significantly different from the other data. If you were to graph the data, you would notice that an outlier would lie “outside” the other data.

 

outlier: a data point that lies significantly outside the general trend of the data

Source: MathWorks 12 Student Book/Teacher Guide.

(Vancouver: Pacific Educational Press, 2011.)


 

Self-Check 2

 

In each set of data, identify the outlier(s), if any, and justify why they are outliers.

  1. 7, 24, 24, 28, 31, 35 Answer
  2. Use the data from the bar graph.

     
    This is a graph displaying the percentage of elementary students that have a cellphone.
    Answer
  3. Use the data from the graph.

     
    This is a graph displaying the monthly number of phone calls made and the age of the caller.

    Answer
Try This 2

 

Use the Mean, Median, Mode activity to explore the effect of outliers on mean, median, and mode.

 

 

This is a play button that opens Mean, Median, Mode.

 

 

Use this table of data sets to answer the following questions.

 

Data Set 1

20, 22, 22, 25, 26

Data Set 2

20, 22, 22, 25, 26, 40

Data Set 3

20, 22, 22, 25, 26, 100
  1. Find the mean, median, and mode for each data set using the Mean, Median, Mode interactive. Record your solutions in a table similar to the following.

    Central Tendency Measure

    Mean

    Median

    Mode

    Data Set 1

     

     

     

    Data Set 2

     

     

     

    Data Set 3

     

     

     
  2. Rank mean, median, and mode from the least to most affected by adding one outlier to Data Set 1.

course folder Save your responses in your course folder.

 

Share 1

 

With a partner or in a group, share your answers to Try This 2. If you have answers that differ, share strategies and try to make corrections. If you can’t agree on an answer, consult your teacher.

 

course folder If required, place a summary of your discussion in your course folder.