HP 48gII hp 48gII_user's manual_English_E_HDPMSG48E67_V2.pdf - Page 580

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: Page 18-9