Transcript Document

Data Frequency Tables
and Line Plots
Joseph Williams
Modified by
Charlotte Stripling
M7D1.b Construct frequency Distributions
Objective: Create and interpret frequency
tables and line plots.
Vocabulary
Data - information, often given in the form
of numbers or categories.
Frequency Table – a table that displays
the number of times each item or category
occurs in a data set.
Line Plot – a number line diagram that
uses X marks to show the frequencies of
items being tallied.
Line Plot Example
Students at a Party
Making a Frequency Table
Numerical Data: Data consisting of
numbers, not categories.
Numerical Questions: How many books
have students read last month?
Books Students Read Last Month (numerical)
# of Books
1
2
3
4
5
6
7
Tallies
llll
llll
llll l
ll
Frequency
5
5
6
2
llll
4
students
Making a Line Plot
Is a visual of the frequency distribution.
Line plots are NOT used for categorical
data.
Draw a number line whose scale starts
at or before the minimum data value
and stops at or after the maximum data
value. Use a consistent increment.
Completed Line Plot When the items being tallied are numbers, a line plot
can be used to visually display numerical data. A line
plot uses X marks above a number line to show the
frequencies.
The X marks above
X
The Number Line X
shows the number X
of books read.
X
X
1
X
X
X
X
X
X
X
X
X
X
X
the number line show
the frequencies.
X
X
X
X
X
X
2
3
4
5
Number of Books Read
6
7
Making a Frequency Table
Categorical data: data that can be
placed into categories.
Categorical question: What is your
favorite color?
NOTE: Categorical data can be shown in a
frequency table but not a line plot.
Completed Frequency Tablepeople
Favorite Color (category)
Color
Blue
Red
Yellow
Purple
Orange
Green
Black
Tallies
llll
lll
l
ll
llll
Frequency
5
3
1
2
4
ll
2
Variability in Data Distributions



Outliers-Unusually high or low values in a
distribution.
Clusters-An group of data values with
higher frequency than surrounding values.
Gaps-Areas in the scale where there is a
lack of data values.
Analyze the Data
Now look at the Frequency Tables
and the Line Plots from your notes
to see if you can identify any
outliers, clusters or gaps.