systematically collect, organize, and describe data
construct, read, and interpret tables and graphs
make inferences and convincing arguments based on data analysis
Discuss physical growth and have students hypothesize about one's height
in relation to the lengths of arms, legs, feet, etc.
Have students survey a set group of people, noting each individual's height
and arm span (length from left middle fingertip to right middle fingertip
when arms are outstretched).
Students will then organize the collected data in a three column table
whereby the first column represents the person's name, the second column
will represent that person's height, and the third column will represent
their arm span in cm.
Using graph paper, guide students in making a graph with a vertical and
a horizontal axis, with the vertical axis (Y) representing arm span, and
the horizontal axis (X) representing height.
Refer to tables and guide students in plotting a point where the two sets
of data for each person meet. For example, find Mary's height on
"x", and Mary's arm span on "y". Trace each line and place a point
where the lines intersect. Graph all points. This is a scatter
When all points have been plotted, students will observe a TREND, or pattern.
To determine what kind of correlation they are looking at it, students
should try to draw a straight line, or a line of best fit, through the
points so that the line is as close to all points as possible. Note:
If the students have trouble doing this, have them visualize the line as
an arrow pointing either upward or downward to the right, showing the direction
in which the data point.
Note the three types of correlation and what they mean:
a) positive correlation - when one
set increases, so does the other (as Mary's height increases, her arms
will get longer).
b) negative correlation - when
one set increases, the other decreases (the further North latitude, the
lower the temperature)
c) no correlation - there
is no relationship between the two sets of data ( as Mary's height increase,
it does not change her IQ)
Have the students draw conclusions based on their graphs and explain
any correlations they find. Students may also make predictions about
a person's arm span based on that person's height. Students might
prepare a presentation or a final paper according to a teacher made outline.
Some suggested questions to consider:
Describe the trend you see in the scatter plot.
Which shows the trend better, the table or scatter plot?
Which point(s) fit the trend the least? Why do you think that is?
Would you ever expect to see all points on a perfectly straight line?
Why or why not?
This lesson could be modified and done for different sets of data which
would enable students to observe all three types of correlation.