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The first lesson I do with the kids is the
family lesson. We go outside where a line has been painted (or
drawn) on the ground. I have added spaced large numbers from
1 - 10 on the line.
Question: How many people are in your family?
Direction: Find the number that represents
the number of people who actually live in your house and to whom
you are related. For example they are your mother, father, sister
or brother. Do not count aunties, uncles, cousins, grandparents
or pets!
The boys and girls should create something
like this:
I take a picture of this grouping by standing
on a chair. If you do not have a digital camera and a way to
show the picture have one student stand on the chair and sketch
what he/she sees like this:
Ravid draws the grouping |
Kyle transfers the data to the class
chart |
Allsion labels the chart |
Two examples from individual math
journals
When we get back into the room we look at
the sketch or the photo and I get the kids to realize it is a
graph. I am able to illicit through discussion the following
information:
- It is a graph
- It shows data for one piece of information:
How many people in our families
- There is no one on the number one
- One line has many people and several lines
have few people
I have one person recreate the picture on
the board (or a piece of chart paper) and everyone creates it
in their personal Math Journal
This is a line plot. It shows organized data
for one piece of information. All graphs must have a title.
Question: What shall we call our line plot?
Have the students label or name the line plot
On the chart and in the math journals we now
list the information we can glean from a line plot
- We can find the number of people in families
that occurs most frequently in our class
- We can find the difference between the least
number of people in families and the most number of people in
families
- We can find what the average number of people
in families in our class
- We can find the middle of the data for number
of people in families
We can find the number
of people in families that occurs most frequently in our class
the MODE
Finding the mode is one way that we summarize
and describe data. The mode is the number that occurs most often
in a set of data. There can be more than one mode if there are
two or ore numbers that occur the same number of times. page
59, Addison-Wesley, Math-a-pedia.
The mode for our line plot.
Mode
means MOST
The data column with the most is
"4" |
We can find the difference
between the least number of people in families and the most number
of people in families
the RANGE
|
The range for our line plot.
RANGE
is highest data number minus the lowest data number
The highest data number is 8 minus
the lowest 2 =
The RANGE is "6" |
We can find what the
average number of people in families in our class
the MEAN
|
The mean, often called the average,
is a number that summarizes a set of data. To find the mean,
add all of the numbers in a data set, and then divide the sum
by the number of items in the set. page 55 Addison-Wesley, Math-a
-pedia.
2+3+(4x11)+(5x9)+(6x3)+(7x2)+(8x3)
divided by 30
The MEAN is "5" |
We can find the middle
of the data for number of people in families
the MEDIAN
|
Finding the median is one way
to describe and summarize a set of data. The median is
the middle number when numbers are arranged in order of their
value. That means that the number of data pieces above the median
will be the same as the number of data pieces below the median.
The median helps us see how data are distributed.
page 58, Addison-Wesley, Math-a-pedia
The MEDIAN is "5" |
Two ways to find the MEDIAN
|
To figure the center of the data divide the
total number of x's by 2. Next start at the first x on the first
number of your line plot and count the same number of x's as
the answer to the above question
Total number of x's divided by 2 = |
To figure the center of the data put one finger
on the first x in your line plot and using your other hand, one
finger on the last x in your line plot. Correspondingly move
each finger forward on the line plot until they meet. The x they
meet on is the median. |
You have now introduced the vocabulary
needed to understand line plots: Mode, Range, Mean and Median. It is important that you impress on the students
that a line plot is used to show data on ONE piece of information.
That is why line plots only have a title or label on the x axis
and nothing on the y axis. |
