Frequency polygons - Graphing Data

Frequency polygons

Lessons

Notes:
Frequency Polygons are graphs that are constructed out of a frequency table. To create a Frequency Polygon just follow these steps:
1) Create a histogram
2) Plot the midpoints for each bar on the histogram
3) Plot a point with a value of zero one bar below the smallest class. Also plot a point with a value of zero one bar above the largest class
4) Connect all the data point with a straight line
  • 2.
    Constructing a Frequency Polygon from a Frequency Distribution
    The following frequency table shows the amount of time it took 45 ski racers to complete a ski course:

    Lower Limit:

    Upper Limit:

    Frequency:

    Cumulative Frequency:

    80 seconds

    86 seconds

    3

    3

    86 seconds

    92 seconds

    5

    8

    92 seconds

    98 seconds

    12

    20

    98 seconds

    104 seconds

    8

    28

    104 seconds

    110 seconds

    16

    34

    110 seconds

    116 seconds

    11

    45

  • 3.
    Interpreting a Frequency Polygon
    The frequency polygon below shows the wind speed during a particular day in San Francisco Bay:
    Frequency polygons
Teacher pug

Frequency polygons

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