With grouped data on pages (0-99, 100-199, 200-299, etc.), if converted to a frequency distribution graph, what kind of graph should be used?

With grouped data on pages (0-99, 100-199, 200-299, etc.), if converted to a frequency distribution graph, what kind of graph should be used?

• A. A bar graph
• B. A histogram
• C. A polygon
• D. Either a histogram or a polygon

Answer: (D)

Grouped data in equal-width class intervals can be shown effectively with graphs that reflect frequencies across consecutive classes. A histogram does this by drawing touching bars for each class interval, with height showing the frequency and the continuous classes implied by the touching bars. A frequency polygon offers a different but equally valid view: plot the frequency at each class midpoint and connect the points with straight lines to reveal the distribution’s shape. For these 0–99, 100–199, 200–299, etc., the midpoints are around 49.5, 149.5, 249.5, and so on, and the bars or the line would reflect the same underlying frequencies. Because the data are grouped into contiguous intervals, either a histogram or a frequency polygon is appropriate.

Grouped data in equal-width class intervals can be shown effectively with graphs that reflect frequencies across consecutive classes. A histogram does this by drawing touching bars for each class interval, with height showing the frequency and the continuous classes implied by the touching bars. A frequency polygon offers a different but equally valid view: plot the frequency at each class midpoint and connect the points with straight lines to reveal the distribution’s shape. For these 0–99, 100–199, 200–299, etc., the midpoints are around 49.5, 149.5, 249.5, and so on, and the bars or the line would reflect the same underlying frequencies. Because the data are grouped into contiguous intervals, either a histogram or a frequency polygon is appropriate.