Histograms

Histograms

HistogramsPresented by William2!(William Chen and Gulian)What it isA histogram looks like a bar graph but instead divides the data set into different ranges. Over each range is placed a block or rectangle whose height represents the number of data values in the range. A frequency histogram uses vertical columns to show frequencies (without using ranges) such as :How many times a score occurs

When to useTo group numbers in a data set into ranges WeightHeight Age TimeShow frequencies (without using ranges)

Data neededOne numerical data setRanges to group the data set in (unless creating a frequency histogram)TitleAxes Labels

Real Life ExampleHow long is your bus ride to/from school? Your answers (in min.):

How we did itPrerequisites (for both):Collect data.Decide ranges to group data in.*Computer:Enter data in Microsoft Excel.Select data and insert Column/Bar Graph.Select the bars on the chart, right-click, then select Format Data Series.Slide the Gap Width slider all the way to No Gap.Customize so it is creative/original! Handwritten: Draw x- and y- axes and label the x-axis as your ranges/numbers and your y-axis as frequencies. Draw your bars like in a bar graph but with no gaps in between. (This is a difference between a bar graph and histogram.) Decorate! *Skip step if you are creating a frequency histogram.

(If you are making a frequency histogram, dont use ranges.)Checking for UnderstandingWhat percentage of the class has bus rides longer than 20 minutes? About 43%

Advantages vs. DisadvantagesNumbers are grouped into ranges so that trends can be observedCan show frequenciesActual data (numbers) not actually seenCan only graph one data set

Thank you!http://www.mathsisfun.com/data/histograms.htmlhttp://www.google.com/imghp?hl=en&tab=wiThe combined brainpower of William2!