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→Histogram & Bar Chart
=== What is a histogram? ===
=== What is a histogram? ===
A histogram is a plot
A histogram is a plot
and the raw data it was constructed from, is shown below:
and the raw data it was constructed from, is shown below:
[[File:KOER-%20Mathematics%20-%20Statistics_html_6201ec25.png]]
[[File:KOER-%20Mathematics%20-%20Statistics_html_6201ec25.png]]
67 45 22 48 91 46
67 45 22 48 91 46
52 61 58 55
52 61 58 55
=== How do you construct a histogram from a continuous variable? ===
=== How do you construct a histogram from a continuous variable? ===
To construct a
To construct a
histogram from a continuous variable you first need to split the data
histogram from a continuous variable you first need to split the data
the frequencies in each bin have been tabulated along with the scores
the frequencies in each bin have been tabulated along with the scores
that contributed to the frequency in each bin (see below):
that contributed to the frequency in each bin (see below):
Bin Frequency Scores
Bin Frequency Scores
90-100 1 91
90-100 1 91
Notice that, unlike a
Notice that, unlike a
bar chart, there are no "gaps" between the bars (although
bar chart, there are no "gaps" between the bars (although
decide whether you round up or round down scores on the boundaries of
decide whether you round up or round down scores on the boundaries of
bins)
bins)
=== Choosing the correct bin width ===
=== Choosing the correct bin width ===
There is no right or
There is no right or
following histograms use the same data but have either much smaller
following histograms use the same data but have either much smaller
or larger bins, as shown below:
or larger bins, as shown below:
[[File:KOER-%20Mathematics%20-%20Statistics_html_75ab55c3.png]]
[[File:KOER-%20Mathematics%20-%20Statistics_html_75ab55c3.png]]
We can see from the
We can see from the
data.
data.
Histograms are based on
Histograms are based on
area not height of bars
area not height of bars
In a histogram, it is
In a histogram, it is
spaced bars (bins) and, under these circumstances, the height of the
spaced bars (bins) and, under these circumstances, the height of the
bin does reflect the frequency.
bin does reflect the frequency.
=== What is the difference between a bar chart and a histogram? ===
=== What is the difference between a bar chart and a histogram? ===
nominal data sets.
nominal data sets.
== Circle or Pie Chart ==
== Circle or Pie Chart ==
