HP 48gII User Manual

Page 580

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Page 18-9


Histograms
A histogram is a bar plot showing the frequency count as the height of the
bars while the class boundaries shown the base of the bars. If you have your
raw data (i.e., the original data before the frequency count is made) in the
variable

ΣDAT, you can select

Histogram

as your graph type and provide

information regarding the initial value of x, the number of bins, and the bin
width, to generate the histogram. Alternatively, you can generate the column
vector containing the frequency count, as performed in the example above,
store this vector into

ΣDAT, and select

Barplot

as your graph type. In the

next example, we show you how to use the first method to generate a
histogram.

Example 1 – Using the 200 data points generated in the example above
(stored as a column vector in

ΣDAT), generate a histogram plot of the data

using X-Min = 10, Bin Count = 16, and Bin Width = 5.

• First, press „ô (simultaneously, if in RPN mode) to enter the PLOT

SETUP screen. Within this screen, change Type: to Histogram, and check
that the option Col: 1 is selected. Then, press

L@@@OK@@@.

• Next, press „ò (simultaneously, if in RPN mode) to enter the PLOT

WINDOW – HISTOGRAM screen. Within that screen modify the
information to H-View: 10 90, V-View: 0 15, Bar Width: 5.

• Press @ERASE @DRAW@ to generate the following histogram:


• Press @CANCEL to return to the previous screen. Change the V-view and Bar

Width once more, now to read V-View: 0 30, Bar Width: 10. The new
histogram, based on the same data set, now looks like this:

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