Enhancing Learning With a Graphics Calculator - CasioEd

Creating histograms
In Manual mode, you will also need to change the View Window settings (otherwise the
histogram will look very small). Use the values shown below; only the Y values need to be
changed, to accommodate the new relative frequencies to be represented.
When the graph is drawn, it will look like this (much the same as previously).
You will notice a difference if you TRCE the histogram, as the “ f= ” values now show
relative frequencies, rather than frequencies.
The percentage frequency histogram could be done following a similar procedure, after
entering the percentage frequencies into List 4 and re-defining StatGraph1 accordingly. This
time change the Y range to about -10 ≤ y < 40, with a scale of 5, for the percentage
frequencies. Try this for yourself, and notice that he shape is similar, although the percentage
frequencies are shown when you trace.
Calculating relative and percentage frequencies quickly
Calculating relative frequencies and percentage frequencies as you did above is a bit tedious
and it is easy to make an error since many calculations are involved. A better strategy is to get
the calculator to do this for you.
Start by deleting the data previously placed into List 3 and List 4. (It is these that we will
calculate automatically.)
Now highlight an empty list into which the calculated relative frequencies will be stored. To
do this, move the cursor to the name of the list at the top of the screen, as shown in the next
screen. (Notice that the name of the list is shown in reverse print).
We are going to define List 3 as List 2 divided by 186. That is, the relative frequency for each
interval is the frequency divided by 186, as you did by hand. To do this press OPTN then
LIST (F1) and List (F1) again.
The word List should appear near the bottom of the screen. Use it to complete the definition
as shown on the two screens below.
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