Creating Box Plots with a Graphing Calculator Todays

Creating Box Plots with a Graphing Calculator

Today’s Learning Goal n We will begin to understand how to create and interpret box plots with a graphing calculator.

Box-and-Whisker Bag Blue 5 6 7 8 9 12 9 15 7 21 13 11 16 8 10 11 16 13 1 2 3 4 n n Previously, we made a box-and-whisker plot for the data at the left using the five-number summary. What are the five numbers we need to create a box-and-whisker plot? Awesome… 1) the minimum 2) the first quartile (Q 1) 3) the median (Q 2) 4) the third quartile (Q 3) 5) the maximum

Using the Graphing Calculator Bag Blue 5 6 7 8 9 12 9 15 7 21 13 11 16 8 10 11 16 13 1 2 3 4 n n n We can use our graphing calculators to make box plots for data also. To put data into your calculator, press the “STAT” button as we did before. Now press “ENTER” to select the edit screen to put data in. STAT Enter

Using the Graphing Calculator Bag Blue 5 6 7 8 9 12 9 15 7 21 13 11 16 8 10 11 16 13 1 2 3 4 n n n If you have data in your lists, you can clear the list by putting the cursor over top of the L 1 (or L 2) at the top and pressing “CLEAR”. Now put the following blue M&M data down the L 1 column. Make sure you have 11 total data points for all 11 bags. Clear

Using the Graphing Calculator Bag Blue 5 6 7 8 9 12 9 15 7 21 13 11 16 8 10 11 16 13 1 2 3 4 n n n Now that you have the data in the calculator, press the “ 2 nd” button and then the “Y=” button to access the statistical plot screen. Y= 2 nd Press “Enter” to enter the Stat -Plot screen. Make your Stat-Plot screen match the one shown at the right by pressing “ENTER” with your cursor over each highlighted part. Enter

Using the Graphing Calculator Bag Blue 5 6 7 8 9 12 9 15 7 21 13 11 16 8 10 11 16 13 1 2 3 4 n n n Press the “Window” button and make the x-values go from 0 to 25 by 5 s and the yvalues go from 0 to 5 by 1 s. Press “Graph” to view the box plot of the data. Press the “Trace” Button and you will see some information pop up. Win Trace Graph

Using the Graphing Calculator Bag Blue 5 6 7 8 9 12 9 15 7 21 13 11 16 8 10 11 16 13 1 2 3 4 n n n Notice that it tells you the median is 13 blue M&Ms at the bottom of the graph. If you press the right and/or left directional arrows, you can trace to the min, max, Q 1, and Q 3 values also! What is the third quartile for this data? Fantastic…Q 3 = 16! <

Using the Graphing Calculator Bag Red 1 2 3 4 n 18 22 5 6 7 8 9 9 23 21 20 17 19 24 10 11 27 34 If we wanted to make more than one box plot, we can use our graphing calculators to do that also. STAT n n Suppose we wanted to put the Red M&M data into our calculator. What button should we push to enter data? Nice…”STAT”. Now press “ENTER” to select the edit screen to put data in. Enter

Using the Graphing Calculator Bag Red 1 2 3 4 n 18 22 5 6 7 8 9 9 23 21 20 17 19 24 10 11 27 34 n n n Now put the following red M&M data down the L 2 column. Make sure you have 11 total data points for all 11 bags. Y= 2 nd Now that you have the data in the calculator, press the “ 2 nd” button and then the “Y=” button to access the statistical plot screen. Notice Plot 1 is still On for the blue M&M data. Cursor down to Plot 2 and Press Enter

Using the Graphing Calculator Bag Red 1 2 3 4 18 22 5 6 7 8 9 9 23 21 20 17 19 24 10 11 27 34 n Make sure your Plot 2 screen looks like the one at the right. Graph n n n Be sure to tell the calculator that the red M&M data is coming from the L 2 list by pressing the “ 2 nd” and “ 2” buttons. Press “Graph” to see both box plots. What is wrong with our graph? We cannot see the maximum! 2 nd 2

Using the Graphing Calculator Bag Red 1 2 3 4 n 18 22 5 6 7 8 9 9 23 21 20 17 19 24 10 11 27 34 What can we do to be able to see the maximum for the Red M&M data? Great…change the window. n Press “Window”. What should we change the x-max to so that we can see the entire box plot? Good…anything more than the maximum red data point of 34. Win

Using the Graphing Calculator 1 2 3 4 n 18 22 5 6 7 8 9 9 23 21 20 17 19 24 10 11 27 34 n n Let’s make the x-max be 40. Then, press “Graph” to see the box plots again. Again, you can press “Trace” to see the 5 -number summary values. If you press the cursor up/down buttons it will toggle between the two box plots. Trace < Bag Red Graph

Partner Work n You have 30 minutes to work on the following questions with your partner.

For those that finish early n Use your graphing calculator to make a box plot of the following data that shows the ages of forty drivers killed in car crashes using an interval size of 10. 37, 76, 18, 81, 28, 29, 18, 27, 20, 18, 17, 70, 87, 45, 32, 88, 20, 18, 28, 17, 51, 24, 37, 24, 21, 18, 17, 40, 25, 16, 45, 31, 74, 38, 16, 30, 17, 34 n According to the box plot, which age range seems to be the most likely to be killed by a car crash?

Big Ideas from Today’s Lesson n Using a graphing calculator helps to minimize the time it takes to make a graph and it allows you to focus on its interpretation and meaning.

Homework n n Use your graphing calculator to make the box plots on the following pages of your textbook. Then, make a sketch of the box plot. Pgs. 620 – 621 (14, 15)