Data Distribution - Histograms
Data Distribution - Histograms
Histogram – a graph used to show data
distribution in which the horizontal axis
displays groups of data called bins and
the vertical axis shows the frequency of
the data in each bin
Data Distribution - Histograms
Create a histogram for the following data
representing the sales made by a salesperson
per day for a month.
2 2 3 5 10 3 4 2 3 3 4 6 8 7
5 12 2 8 8 3 4 14 14 10 6 7 8
3 11 7
Data Distribution - Histograms
• Step 1 – The data will be broken into groups called bins so choose a
bin size and the bins to use.
For example a bin of 0 – 3 would represent the days where 0 – 3
sales were made.
The smaller the bin size the more specific you can be about where
the data is, but the more bins will result.
0-3
3–6
6–9
9 – 12
12 – 15
Data Distribution - Histograms
• Step 2 – Create a frequency table, using your
bins, and determine how many values are in
each bin.
frequency
0 – 3 This is for all values from 0 up to but not including 3
3 - 6 This is for all values from 3 up to but not including 6
6 -9
9 -12
12- 15
Data Distribution - Histograms
• Step 2 – Create a frequency table, using your bins, and
enter the data.
frequency
0 – 3 This is for all values from 0 up to but not including 3 4
3 - 6 This is for all values from 3 up to but not including 6 11
6 -9 9
9 -12 3
12- 15 3
Step 3 – Draw the histogram
Frequency
0 3 6 9 12 15
Bins
• Step 4 – Sometimes the mean and median
are identified on the histogram with
vertical lines.
Mean = 6.2
Median = 5.5
median mean
Frequency
0 3 6 9 12 15
Bins