Frequency Polygons and Ogives Chapter 2.2 Frequency Polygons and Ogives

The frequency polygon The frequency polygon is a graph that displays the data by using lines that connect point plotted for the frequencies at the midpoints of the classes. The frequencies are represented by the heights of the points

Record High Temperatures for Each State Class Limits Class boundaries Class Midpoint Frequency 100-104 99.5-104.5 2 105-109 104.5-109.5 8 110-114 109.5-114.5 18 115-119 114.5-119.5 13 120-124 119.5-124.5 7 125-129 124.5-129.5 1 130-134 129.5-134.5

Steps for creating a frequency polygon Find the midpoints of each class. Draw and label the x and y axes. Label the x- axis with the midpoints of each class, the y- axis as frequency Plot the points, x values = midpoints, y values = frequency Connect adjacent point with line segments. Connect to x-axis at beginning and end of graph

Frequency Polygon for High Temperatures

Frequency Table for MPG of SUVs Class Class boundaries Class Midpoint Frequency 12 11.5-12.5   6 13 12.5-13.5 1 14 13.5-14.5 3 15 14.5-15.5 16 15.5-16.5 8 17 16.5-17.5 2 18 17.5-18.5 19 18.5-19.5

Frequency Polygon for MPG of SUVs

Ogive The ogive is a graph that represents the cumulative frequencies for the classes in a frequency distribution.

Steps for creating an Ogive Find the cumulative frequency for each class Draw the x and y axes. Label x-axis with class boundaries, y-axis cumulative frequencies Plot the cumulative frequency Connect adjacent points with line segments

Cumulative Frequency for MPG of SUVs    Cumulative Frequency  less than 11.5  less than 12.5  less than 13.5  less than 14.5  less than 15.5  less than 16.5  less than 17.5  less than 18.5  less than 19.5 :

Ogive for MPG of SUVs

Real Estate Activity Creating Frequency Distributions Histograms Frequency Polygons And Ogives