Statistics and Probability / Introduction to Histograms

Understanding

Students explore how changing the bin width can change the story in the distribution of the data.

What to look for

Note that histograms are ordered according to a number line and are used with quantitative data while bar graphs have no inherent order and are used to indicate some feature of qualitative data.

Sample Assessment

The graph below displays the heights of cherry trees in a park in Washington DC. The first bin width is [60,65).
Height of Cherry Trees

Which interval contains the median height of the cherry trees?

Answer: [75, 80)

The Big Idea

Histograms are particularly useful for very large data sets where a dot plot would be difficult to manage.

What are the students doing?

Students compare different bin widths for the same data and explore the effect of adding data points to a histogram.

What is the teacher doing?

Help students remember the importance of thinking about shape, center and spread when talking about distributions of data.