1. To graph and interpret Box-and-Whisker Plots 9/17/13 Do Now: Order the set of numbers from least to greatest, then find the median.

2. The Median

3. 3. Find the lower and upper medians or quartiles. These are the middle numbers on each side of the median. What are they? Step 3 – Upper & Lower Quartiles

4. Now you are ready to construct the actual box & whisker graph. First you will need to draw an ordinary number line that extends far enough in both directions to include all the numbers in your data: Step 4 – Draw a Number Line

5. Locate the main median 12 using a vertical line just above your number line: Step 5 – Draw the Parts

6. Locate the lower median 8.5 and the upper median 14 with similar vertical lines: Step 5 – Draw the Parts

7. Next, draw a box using the lower and upper median lines as endpoints: Step 5 – Draw the Parts

8. Finally, the whiskers extend out to the data's smallest number 5 and largest number 20: Step 5 – Draw the Parts

9. Step 6 - Label the Parts of a Box-and- Whisker Plot Q3Q1 Name the parts of a Box-and-Whisker Plot MedianUpper Quartile Lower Quartile MinMax

10. Interquartile Range The interquartile range is the difference between the upper quartile and the lower quartile. 14 – 8.5 =5.5

11. Upper Quartile = 10 Q3Q3 Lower Quartile = 4 Q1Q1 Median = 8 Q2Q2 3, 4, 4, 6, 8, 8, 8, 9, 10, 10, 15, Find the median, quartiles and inter-quartile range. 6, 3, 9, 8, 4, 10, 8, 4, 15, 8, 10 Order the data Inter-Quartile Range = 10 - 4 = 6 Construct a box plot for this data.

12. Applications of Box Plots A box-and-whisker plot helps to show how varied, or spread out, the data are. Box plots are useful for comparing two or more sets of data.

13. 130140150160170180190 Boys Girls cm Box and Whisker Diagrams. Box Plots E mma recorded the heights in cm of students in the same class and constructed a box plot from the data. The box plots for both boys and girls are shown below.

14. Interpreting a Box-and-Whisker Plot The large box (IQR) represents about half of the data. Each small box represents about one quarter of the data. Each whisker represents about one quarter of the data

15. Activity 1.3 Construct a box-and-whisker plot for the following data: Math test scores 80, 75, 90, 95, 65, 65, 80, 85, 70, 100, 50

16. Additional Practice http://www.warrick.k12.in.us/school s/castlesouth/docs/Math/Math7Boo k/Math%207%20Ch%203.4%20p1 23.pdf http://www.warrick.k12.in.us/school s/castlesouth/docs/Math/Math7Boo k/Math%207%20Ch%203.4%20p1 23.pdf