1. Measures of Central Tendency

2. 5 Number Summary Minimum (lowest number) First Quartile
Median (second Quartile)
Third Quartile
Maximum (highest number)

3. What does a graph of the five number summary look like?
A boxplot!

4. Anatomy of a Box and Whisker Diagram.
Lower Quartile
Upper Quartile
Lowest Value
Highest Value
Whisker
Boxplot
A boxplot is a graph of a five-number summary.
A central box spans the quartiles Q1 and Q3
A line in the box marks the median (M)
Lines extend from the box out to the smallest and largest numbers.
Anatomy of a Box and Whisker Diagram.
Median

5. Boxplot organizer!

6. To make a box and whisker plot: 1st: Write the data in order
Use the temperatures: 84, 80, 78, 81, 83, 76, 82, 80
Mean: the average
Add
Divide total number
Median: the middle number
Write the numbers in order, smallest to greatest.
Find the middle
If two in middle, take average of them
Mode: Most frequent number.
There can be none, one, or many modes.
Range:
Highest - Lowest
First Quartile Q1
Median lower half
Third Quartile Q3
Median upper half
InterQuartile Range:
IQR
Q3 – Q1
Outlier:
1 High, 1 Low
Q1 – 1.5(IQR)
Q (IQR)
To make a box and whisker plot:
1st: Write the data in order
____ ____ ____ ____ ____ ____ ____ _____
Range: Highest – Lowest
_______________________
Q1:
Median lower half
Find the median, put a box around it.
Q3: Median Upper Half.
IQR: Q3 – Q1:______________

7. Min: Q1: Median: Q3: Max: Mode: Range: IQR: Mean: 75 76 77 78 79 80 8182 83 84 85

8. Example 1: Draw a Box plot for the data below and give the mode, range, IQR and mean
Drawing a Box Plot.
4, 5, 6, 8, 8, 8, 9, 9, 9, 10, 12
Mode:
Range:
IQR:
Mean:

9. Example 2: Draw a Box plot for the data below and give the mode, range, IQR and mean
Drawing a Box Plot.
3, 4, 4, 6, 8, 8, 8, 9, 10, 10, 15
Mode:
Range:
IQR:
Mean:

10. Drawing a Box Plot.
Example 3: Draw a Box plot for the data below and give the mode, range, IQR and mean
6, 22, 4, 15, 14, 8, 8
Mode:
Range:
IQR:
Mean:

11. Drawing a Box Plot.
Example 4: Draw a Box plot for the data below and give the mode, range, IQR and mean
10, 15, 12, 20, 25, 22, 29
Mode:
Range:
IQR:
Mean:

12. Boxplot Practice Worksheet
Homework
Boxplot Practice Worksheet