1. Histograms
We are learning to…create and analyze histograms and identify misleading graphs.
Saturday, April 15, 2017

2. Histograms vs. Bar Graphs
Many people confuse histograms with a bar graph.
A histogram looks very similar to a bar graph. There are two big differences between a histogram and a bar graph.
A bar graph compares items in categories while a histogram displays one category broken down into intervals. For example:
A bar graph would compare…the number of apples, to the number of oranges, to the number of bananas at a grocery store.
A histogram would compare…the number of people who eat 0-4 apples a week, to the number that eat 5-9, to the number who eat

3. Histograms vs. Bar Graphs
The bars on a histogram touch. The bars found on a bar graph do not touch.
Why do you think that the bars will touch on a histogram?
It will make intervals of data easier to compare.

4. Frequency Chart
A Frequency Chart is a table that breaks data down into equal intervals and then counts the amount data in each interval.
A Frequency Chart is often used to sort a list of data to make a Histogram.
Make a Frequency Chart to display the data below:
90, 85, 78, 55, 64, 94, 68, 83, 84, 71, 74, 75, 99, 52, 98, 84, 73, 96, 81, 58, 97, 75, 80, 78
Interval
50-59
60-69
70-79
80-89
90-99
Frequency of Data 3 2 7 6 6

5. Don’t forget little things…like labels and equal intervals!
Creating a Histogram
Don’t forget little things…like labels and equal intervals!
Interval
50-59
60-69
70-79
80-89
90-99
Frequency of Data 3 2 7 6 10
Math Test Scores 8 6
Frequency 4 2
50-59
60-69
70-79
80-89
90-99
Test Scores

6. Misleading Histograms
What does it the word “misleading” mean?
Deceptive or intentionally create a false impression.
Misleading Histograms.xls
Types of Misleading Histograms
Combing Intervals: The amount of data in each interval can make a histograms look different.
Stretched Graphs: Graphs might be stretched vertically so that data looks larger.
Excluded Intervals: Intervals may be skipped on the x or y-axis to make the data look smaller.