1. Warm Up
1) What is Standard Deviation? 2) Given that the mean of a set of data is 15 and the standard deviation is 3, how many standard deviations away from the mean is 9?

2. Homework
HW-Standard Deviation worksheet ANSWER KEY.pdf

3. Today’s Lesson: Box & Whisker Plots
May 20, 2015

4. Box & Whisker Plots
Who remembers what a Box and Whisker Plot looks like?
Let’s draw a rough sketch!

5. How to set up a Box and Whisker Plot
Things we need to know
Quartiles
Inner Quartile Range
Maximum/Minimum
Median

6. Quartiles
Quartiles- are the values that divide a data set into four equal parts.
The median (or Second Quartile( 𝑸 𝟐 )) separates the data into upper and lower halves.

7. Quartiles
The first quartile ( 𝑸 𝟏 ) is the median of the lower half of the data.
The third quartile ( 𝑸 𝟑 ) is the median of the upper half of the data.
For a set of data that has an odd number of values, you do not include the median in either half when finding the first and third quartiles.

8. Interquartile Range
Interquartile Range- is the difference between the third and first quartiles. Below is an example of everything…..

9. Now Let’s Practice
Summarizing a Data Set Example 1 What are the minimum, first quartile, median(second quartile), third quartile, and maximum of the data set below. 125, 80, 140, 135, 126, 140, 350, 75 Step 1: Arrange the data in order from least to greatest

10. Summarizing a Data Set Continued….
Step 2: Find the minimum, maximum, and Median

11. Summarizing a Data Set Continued….
Step 3: Find the first quartile and the third quartile

12. You Try(1)!!!
What are the minimum, first quartile, median(second quartile), third quartile, and maximum of each data set?

13. Box-and-Whisker Plot
A box-and-whisker plot is a graph that summarizes a set of data by displaying it along a number line. It consists of three parts: a box and two whiskers

14. About Box-and-Whisker Plots

15. Let’s use our “You Try” problems to create a Box-and-Whisker Plot
You Try(1A): Min:_____ 𝑄 1 :______ Median:______ 𝑄 3 :______ Max:______ You Try(1B): Min:_____ 𝑸 𝟏 :______ Median:______ 𝑸 𝟑 :______ Max:______

16. Interpreting Box-and-Whisker Plots
First Identify where are the interquartile ranges located on each map

17. Tired of finding all of the summary statistics data?
Well guess what?
You can find all of your data in the calculator as well!!!!
Step 1: put your data in 𝐿 1
Step 2: Press STAT - - CALC- - 1-Var Stats- -Enter
If you scroll down you will see your quartile values, Min, Max, and Median

18. Use Your Calculator to find the summary statistics and Create a Box-and-Whisker Plot

19. Finding Outliers
Recall…… Outlier- a data value that is much greater or less than the other values in the set. We can identify an outlier if it is greater than 𝑸 𝟑 + 1.5(IQR) or Lower than 𝑸 𝟏 _ 1.5(IQR)

20. Finding Outliers
a. Determine if there are any outliers in this data set.
(Use your calculator to get your 𝑸 𝟏 and 𝑸 𝟑 then use the formulas to find the outliers)

21. Use Your Calculator to Create a Box-and-Whisker Plot
Everyone Should have a handout of how to actually graph a Box-and-Whisker Plot in your calculator
You may read those instructions and work on the problems that go along with it!