1. Lesson 6.7: Box-and-whisker plots
Recall: Median:
The middle number in set of data ordered least to greatest, cuts the data in half.
How can we cut something into quarters?
Median(Second Quartile): Middle of data, cuts data in half
First (Lower) Quartile: median of the lower half of the data, cuts lower half of data in half (creates 2 quarters)
Third (Upper) Quartile: median of the upper half of data, cuts upper half of data in half (creates 2 quarters)

2. Examples: Find the median, first quartile and third quartile
Test scores: 95, 88, 67, 73, 98, 92, 83, 71, 89
List in order: 67, 71, 73, 83, 88, 89, 92, 95, 98
Median = 88
First/lower quartile: 72
Third/Upper Quartile:
93.5
Upper Extreme: Largest piece of data, baring any outliers
Lower Extreme: Smallest piece of data, baring any outliers
What are the upper and lower extremes for the data above?
Upper Extreme = Lower Extreme = 67 98

3. Box-and-whisker Plot: A way to display data to show the “spread” of the data using the median, upper and lower extremes, upper and lower quartiles.
To make a box-and-whisker:
1) Draw a number line consisting of all numbers from at least the lower extreme to the upper extreme
2)Place a dot above or below the number line for the numbers representing the lower extreme, lower quartile, median, upper quartile, and upper extreme.
3)Use the dots representing the upper and lower quartiles to draw the sides of a “box” and connect the sides
4)Draw “whiskers” from upper quartile to upper extreme and lower quartile to lower extreme
5) Draw a vertical line down through the median.

4. Make a box and whisker plot for the test scores data.
Recall: Median = 88
L.Q. = 72
U.Q. = 93.5
L.E. = 67
U.E. = 98

5. In a box and whisker plot, each “chunk” represents 25% of the data.
Each whisker represents 25 % of the data
The box represents the middle 50 % of the data

6. Make a box and whisker plot for the following data: Number days 10 different students were absent from school.
3, 1, 7, 18, 0, 6, 22, 3, 4, 1
0, 1, 1, 3, 3, 4, 6, 7, 18, 22
Median:
3.5
Lower Quartile = 1
Upper Quartile = 7
Lower Extreme =
Upper Extreme = 22

7. p. 378-379, #12-21 multiples of of 3, #24-34 all
Homework :
p , #12-21 multiples of of 3, #24-34 all