Casio fx-7000G vs Casio fx-CG 50: A Comparison of Generating Statistical Graphs

Today’s blog entry is a comparison of how a histogram, normal distribution graphs based on statistical data, scatter plots, and linear regression plot are generated on Casio’s first graphing calculator, the fx-7000G (1985) and the most recent (as of this blog post), the fx-CG 50 (2016). For the curious, the SD2 and LR2 modes are the statistical plot modes of the fx-7000G.

The procedures for the fx-7000G are the same for the fx-6500G, fx-7500G, fx-8000G (and equivalents) and fx-6300G.

The procedures for the fx-CG 50 are the same for the fx-CG 10/20, the fx-9860G series, and fx-9750G series.

Single Variable: Histogram Graphs and Normal Distribution Graphs

The screen shots for this section uses the example data:

Rank #	Rank (List 1)	Frequency (List 2)
1	10	11
2	20	19
3	30	36
4	40	39
5	50	33
6	60	13

Histogram: fx-7000G

1. Enter SD2 mode by pressing [ SHIFT ] [ MODE ] [ × ]. Execute Cls to clear the graph screen and Scl to clear the statistical data registers.

2. There is no automatic zoom adjustment for statistical data on the fx-7000G. Observe the data and set the range accordingly.

3. Count the number of ranks. We have to set aside additional memory registers for the bars. Do this by pressing [ SHIFT ] [ MODE ] [ . ] (Defm mode) and entering the number of ranks. For the data set above, we will need 6 additional registers (Defm 6).

4. Enter the data by using the [x^y] key, which acts as the data entry (DT) key for this mode. The format for each point is: rank ; frequency.

5. Draw the bar graphing by pressing [Graph] [ EXE ]. In other words, run the Graph Y= command without any other arguments. The bar graph can be traced.

(Note: The range I used is: Xmin: 10, Xmax: 70, Xscl: 10, Ymin: 0, Ymin: 40, Yscl: 10)

Normal Distribution Graph: fx-7000G

1. Clear the graph screen by executing Cls.

2. Redo the range. The y-values will have a probability of 1 or less. I like to set Ymin to a very small negative value so that the graph won’t be at the bottom of the screen.

3. Draw the normal graph by pressing [Graph] [SHIFT] [ ↑ ] {Line} 1 [ EXE ]. The command line is Graph Y=Line 1. The normal distribution curve can be traced.

Don’t forget to reset the memory to Defm 0 (or the setting you had) when you are done. Allocating for extra memory registers reduces the amount of program steps available.

Histogram: fx-CG 50

On the fx-CG 50, everything is done through the Statistics Mode. We can use any list from List 1 to List 26, generate multiple data sets and graphs, and on the fx-CG 10/20 and fx-CG 50, the graphs are in color.

1. For this graph, listed the ranks in List 1 and frequencies in List 2. From the main menu, press [ F1 ] {GRAPH}, [ F6 ] { SET }, and either [ F1 ], [ F2 ], or [ F3 ] to choose the graph slot Graph1, Graph2, or Graph3, respectively. Set the Graph Type to Hist.

2. Exit the setup by pressing [ EXIT ], and next press the corresponding graph slot. We will be prompted for the start value (Xmin) and the width (size of the rank). Press [ EXE ]. On the fx-CG 50, we do not have to worry about the window ranges because the Statistics mode automatically zooms the window to fit the data. Nice! The histogram can be traced.

Normal Distribution Graph: fx-CG 50

1. From the main menu, press [ F1 ] {GRAPH}, [ F6 ] { SET }. Change the Graph Type to N-Dist.

2. Exit the set up and press the graph slot. Again, the window zooms to fit the curve. The normal curve can be traced.

Linear Regression: Scatter Plot and Linear Regression Plot

X: (List 1)	Y: (List 2)
-8	-10
-4	-6
-1	0
2	3
5	6
8	8

Scatter Plot: fx-7000G

1. Enter LR2 mode by pressing [ SHIFT ] [ MODE ] [ ÷ ]. Execute Cls to clear the graph screen and Scl to clear the statistical data registers.

2. Adjust the Range (viewing window) to fit the data.

3. Enter the data by using the [x^y] key, which acts as the data entry (DT) key for this mode. The format for each point is: x, y.

If the point occurs more than once, use the format x, y; frequency.

The scatter plot dynamically updates and is shown each time a point is added.

Linear Regression Plot: fx-7000G

The line fits to the equation y = A + Bx (A is the y-intercept, B is the slope).

1. Execute the command Graph Y=Line 1 by pressing by pressing [Graph] [SHIFT] [ ↑ ] {Line} 1 [ EXE ]. The line is then plotted and can be traced. Easy as that.

Scatter Plot: fx-CG 50

Execute the statistics mode and enter the data. Like the histogram and normal distribution plots, the fx-CG 50 automatically adjusts the window to fit the statistical data for the scatter plot and linear regression line.

1. For this graph, List 1 has the x data and List 2 has the y data. From the main menu, press [ F1 ] {GRAPH}, [ F6 ] { SET }, and either [ F1 ], [ F2 ], or [ F3 ] to choose the graph slot Graph1, Graph2, or Graph3, respectively. Set the Graph Type to Scatter. You have an option of selecting the shape of the markers of the point.

2. Exit the setup by pressing [ EXIT ], and next press the corresponding graph slot. The scatter plot will be shown and you can trace the points.

Linear Regression Plot: fx-CG 50

1. While we are on the scatter plot screen, press [ F1 ] {CALC}, then [ F2 ] { X }. We have a choice of two forms: ax+b (default) or a+bx. I chose a+bx to match the fx-7000G.

2. The regression equation, along with the intercept, slope, and correlation are shown. When ready, press [ F6 ] {DRAW}.

3. The regression line is drawn, and the line can be traced.

I hope you enjoyed the comparisons between the classic fx-7000G and modern fx-CG 50.

Until next time,

Eddie

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