How Do We Compare?

Materials needed:

	Height of each student in centimeters
	TI-73 Graphing Calculator
	Student Activity Sheet

Procedures:

Collect the height of the boys and girls in the class. Record the heights in the charts.

Enter the data in the calculator

	Place the number of the girl in L1
	Place the height the girls in L2
	Place the number of the boys in L3
	Place the height of the boys in L4

Let's sort the data in the lists of the calculator

	Sort L2 in numerical order while keeping L1 attached. (SortA(L2,L1)
	Sort L4 in numerical order while keeping L3 attached. (SortA(L4,L3)

Press List and find the following information.

	Minimum height for the boys and girls
	Maximum height for the boys and girls
	Median height for the boys and girls
	Mode height for the boys and girls
	Mean height for the boys and girls

Now let's see how the calculator can find these pieces of information. Start on the homescreen. Press 2nd (STAT) which is LIST and move to the MATH column. You will notice that choices 1-5 will calculate these statistics.

	Select 1. min( . This command will be pasted on the homescreen.
	To enter L2 press 2nd (STAT), which is LIST and choose choice 2.L2. Close the parentheses and then press ENTER

Repeat the last 2 steps to find the minimum and maximum height of both the boys and girls.

Similar find the mean, median, and mode for the heights of both the boys and girls.

Be sure the values in your chart are correct.

Let's look at a box and whisker for the height of the boys and the girls we will set up a box and whisker plot.

Repeat this to set up Plot 2 to graph the data in L4. You will need to set a window to view the graph. Remember the values you entered in L2 and L4.

	Set up a windo for the graph.
	Look at a graph of the data by pressing GRAPH.

	You will see two box and whisker graphs on your screen. The first graph is a box and whisker plot for the girl's heights. The second box and whisker plot is for the boy's heights.
	How are the boxes the same?
	How are the boxes different?
	Compare the whiskers.
	Trace along the graph. You will see a description in the top of the window of which graph you are tracing along. A small box appears on the graph indicating the value you are looking at. The value of the box is indicated at the bottom of the screen.

Compare values on the Graph.

	Compare the Medians of both plots by using the up and down arrows. How is the location of this value different in both box and whisker plots.
	Trace to the right to Quartile 3. Compare these two values on both box and whisker plots.
	Trace to the right to the maximum value. Compare these two values on both box and whisker plots.
	Trace to the left until you reach Quartile 1. Compare these two values on both box and whisker plots.
	Trace to the left to the minimum value. Compare these two values on both box and whisker plots.
	Add these new values to the chart.

Let's suppose the tallest girl and tallest boy in your class left one day and a giant girl and boy are enrolled in their place. The two giants are so tall that they have to bend over when they come through the door. You get several measuring tapes out and find that the boy's height is 300 cm and the girl's height is 250 cm. Cross out the maximum height in each list and add these new heights to the table on your activity sheet where the * is located.

	Return to the calculator and enter these values in L2 and L4 by replacing only the largest height in L2 and L3.
	Look at the box and whisker plot for these new heights. Remember to change the window to reflect these new heights. Press GRAPH to see new box and whisker plots.
	Trace along the box and whisker plots to view values for the minimum, maximum, quartile 1, and quartile 3. Record them on your activity sheet.
	Calculate the mean, median, and mode for the boy's and girl's heights. Record them in your chart.
	Did all the statistics change by adding this giant boy and giant girl to your list?
	Can you explain why some of the values changed and some did not change?