Using your calculator for statistics

Casio fx-7700

 

With the Casio fx7700, you can calculate the most commonly-used descriptive statistics for one variable (mean, standard deviation, sum of values, sum of the values-squared, median, mode) and for regression/correlation between two variables (regression coefficient and intercept, correlation coefficient)

Data are entered and stored in a list (which allows checking that you have entered correctly & keeps the numbers for recalculation) [There is a mode for calculating without storage - not recommended]


This calculator uses a set of function keys F1 through F7 (directly below the screen) whose meanings are indicated in a "menu row" of short names at the bottom of the screen. I have referred to the key names, and indicated the menu name in brackets ([]) immediately after. The same notation is used for the 2d function names on the keyboard (main key name used, 2d function name in brackets). Certain symbols are called by name because they aren't ASCII symbols - Capital sigma is called "Sum", the multiplication siymbol is represented by X, lower-case sigma is called "sigma", the usual division symbol is called "division symbol", and there is a key with a right-pointing arrow [not the cursor key], called "arrow"

For all statistical data entry and calculation, you need to be in the mode "Stat data/STO" (Press MODE, SHIFT, 1).

I. To enter data:

There are three situations in which you enter data - one variable (actual data), one variable (with frequencies - grouped or ungrouped), two variable. Always clear old data before entering new data, or your results will be messed up:

To clear: [You need to be in SD/STO mode - if you aren't, use MODE, SHIFT, 1Sto get there] Press F2[EDIT], F3[ERS], F1[YES] .
 

A. One variable

Press MODE-SHIFT-1 to enter stat data with storage mode. Be sure statistical memory is clear: press F2[EDIT], F3[ERS], F1[YES]
Press MODE, X (multiplication symbol) to indicate 1-variable - this gives the data entry screen.
Enter 1st value, press F1[DT] (display echoes 1st value at the right side), enter 2nd value, press F1[DT] (display echoes 2nd value at right side), etc.
To see the list of data and make corrections: From the data entry screen[Use MODE, SHIFT, 1 and then MODE, X to get to the data entry screen if necessary] press F2[EDIT], (screen shows a table with x-values on left, frequencies on right). To change a value: highlight the value to be changed, enter the the new value (it appears at the bottom of the screen) and press the EXE key (bottom right of keyboard). To remove a value (& not replace it) highlight it and press F1[DEL]. To add a value, first create a place for it by pressing F2[INS], then change the 0 to the value you want (highlight, type your value, press EXE)

B. One-variable with frequencies

Press MODE, SHIFT, 1 to enter stat data with storage mode. Be sure statistical memory is clear: press F2[EDIT], F3[ERS], F1[YES]
Press MODE, X (multiplication symbol) to indicate 1-variable - this gives the data entry screen.
Enter 1st value (it appears at left side), press F3[;] (semicolon appears after the value), enter frequency (it appears after semicolon), pressF1[DT] (display echoes 1st value (only) at the right side), enter 2nd value, press F2[DT] (display echoes 2nd value at right side), etc.
Frequencies must be whole numbers (not decimals or fractions)
To see the list of data and make corrections: From the data entry screen [If necessary, use MODE, SHIFT, 1 and then MODE, X (multiplication symbol) to get to the data entry screen ] press F2[EDIT], (screen shows a table with x-values on left, frequencies on right). To change a value: highlight the value to be changed, enter the the new value (it appears at the bottom of the screen) and press the EXE key (bottom right of keyboard). To remove a value (& not replace it) highlight it and press F1[DEL]. To add a value, first create a place for it by

C. Two-variable

Press MODE, SHIFT, 1 to enter stat data with storage mode. Be sure statistical memory is clear: press F2[EDIT], F3[ERS], F1[YES]
Press MODE, ÷(division symbol) to indicate linear regression with data storage - this brings up the data entry screen
Data are entered as pairs. enter 1st x-value(it shows up at left of screen) SHIFT, (arrow) [,], 1st y-value (you see 1st x, 1st y on the left of screen) F1 [DT] (display echoes x-value (only) at right side). enter 2nd value SHIFT, (arrow) [,] then 2nd y-value F1[DT] (display echoes x-value only), etc.
To see the list of data and make corrections: From the data entry screen[Use MODE-SHIFT-1 and then MODE-X to get to the data entry screen if necessary] press F2[EDIT], screen shows a table with x-values on left, y-values in center, frequencies - all must be 1's- on right. To change a value: highlight the value to be changed, enter the the new value (it appears at the bottom of the screen) and press the EXE key (bottom right of keyboard). To remove an xy-pair (& not replace it) highlight either the x-value or the y-valuet and press F1[DEL]. To add an xy-pair, first create a place for it by pressing F2[INS], then change the 0's in x and y to the values you want (highlight, type your value, press EXE)

II. To Calculate

A. One-variable (either case)

Press MODE, X (multiplication symbol) to get SD (1-variable) mode . For mean and (sample) standard deviation: press F4[DEV] (get new menu) then F1[x-bar], EXE for mean, then F3[x(sigma)n-1], EXE for sample standard deviation. For median, mode, max, min, press F4[triangle] (gives new menu) and press appropriate function key (followed by EXE) for value desired.
To get sum of x's, sum of x-squares, count of values, go back to SD menu screen by pressing PRE (or MODE, X (multiplication symbol)) and press F5[Sum]. In new screen, to get sum of x's, press F2[ Sum x], EXE, to get sum of x-squared press F1[Sum x^2], EXE, to get n press F3[n], EXE.

B. Two-variable

Press MODE (division symbol) to get to regression mode
PressF6[REG] to get to regression calculation screen
For intercept, press F1[A], EXE, for slope press F2[B], EXE, for correlation coefficient press F3[r], EXE.
This calculator uses the form y = A + Bx for the regression line, but does not remind you. [You might want to write on your calculator, or on the inside of the cover, something like A=int, B=slope, because the naming is not standardized]

Errors or questions? Please let me know: cpeltier@saintmarys.edu

Last update 7/20/98

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