Histograms, Frequency Polygons, and Ogives

Histogram: A graph that displays data by using contiguous vertical bars.

Organize Data, Prepare Table Limit BoundaryNumber 10 – – – – – – – – – – – – – – 79.51

Plot the Mid Points

Frequency Polygon: A graph that displays the data by using lines that connect points plotted for the frequencies at the midpoints of the classes.

Plot the Mid Points

Connect the dots, bring down to the x axis

Ogive: A graph that displays the cumulative frequencies for the classes in a frequency distribution.

Organize Data, Prepare Table Limit BoundaryNumber Cumulative 10 – – – – – – – – – – – – – –

Plot the upper boundary points

Connect the dots, start at zero

Relative Frequency Graphs Use relative frequencies when the proportion of data values that fall into a given class is more important than the actual number of data values that fall into the class. Example: Compare age distributions in New York City and Elysburg.

Note that percentages are used. Ages

Distribution Shapes

More Distribution Shapes