begin the lesson, ask students to identify objects which are
approximately one centimeter in size. Students may respond by saying:
- the width of a small fingernail
- the width of a black key on a piano
Next, ask students to identify objects which are approximately one meter in length or height. Students may respond by saying:
- height of a doorknob (the distance from the doorknob to the floor
- the distance from a person's waist to the floor (for a typical adult)
If students have never measured using a meter stick, you may wish to
give them time to practice measuring items in the classroom.
At the start of the measuring activity, each student should be
placed into pairs. Each person in the pair should measure the other's
height (in centimeters) using a meter stick. Since students will need
to use their height data to complete the activity, tell students to
write down their heights on index cards.
Prior to measuring, you may wish to ask students if they already
know their heights. Some students may know their heights, but they may
respond in feet and inches. Caution students to measure their heights
Distribute the Heights of Students in Our Class Activity Sheet to each student.
Heights of Students in Our Class Activity Sheet
Have the students record the heights of ten other students and themselves on the activity sheet.
Have the students order the heights from smallest to largest by
plotting them on the number line at the bottom of the second page of
the activity sheet. Have them plot each height with an x.
Ask the students to determine the middle height of the eleven
heights plotted. Ask why the middle heights is the sixth height.
Explain that the middle height is called the median.
If students are not familiar with the mathematical term median
, lead a discussion which explains its meaning.
Ask the students to determine where the third and ninth heights
fall. Indicate that these points represent the first and third
quartiles, respectively. Ask the students to explain why this result is
so. Have the students draw a box above the area delineated by the third
to ninth heights. Then have them draw a vertical line segment inside
the box denoting the sixth height.
Ask the students to draw a line segment from each edge of the box to
the smallest and largest heights. These lines represent the "whiskers"
of a box‑and‑whisker plot. Ask the student why they think these line
segments are called whiskers.
Have the students complete items 7 through 9 on the activity
sheet. These questions help the students understand how to interpret
the box‑and‑whisker plot. Discuss the responses to these items with the
Students may also complete the box plot using the Box Plotter interactive. Directions for using the tool can be found on the website.
Students can plot the data recorded on their activity sheet and
compare their hand-drawn box-and-whisker plots to the
Dianne Bankard and Francis (Skip) Fennell. The Arithmetic Teacher. September, 1991. pp 26‑33.