Data -

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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.
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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.
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Line Plot Example Students at a Party
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Making a Frequency Table
Numerical Data Data consisting of numbers, not
categories. Numerical Questions How many books
have students read last month?
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Books Students Read Last Month (numerical)
of Books Tallies Frequency
1 llll 5
2 llll 5
3 llll l 6
4 ll 2
5
6
7 llll 4
students
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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.
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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 the number line show the
frequencies.
XXXXXX
XXXXX
XXXXX
The Number Line shows the number of books read.
XXXX
XX
1
2
3
4
5
6
7
Number of Books Read
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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.
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Completed Frequency Table-Favorite Color
(category)
people
Color Tallies Frequency
Blue llll 5
Red lll 3
Yellow l 1
Purple ll 2
Orange llll 4
Green
Black ll 2
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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.

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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.