WARNING - This page is being written based on sketchy notes from work with a previous student. There may be steps missing & I may be referring to keys or menu names by expanded or contracted names. I'd appreciate help & corrections from anyone actually using this calculator.
With the Casio fx9915 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 may be a mode for calculating without storage, but I would recommend ignoring it]
This calculator uses a set of function keys and menu choices whose meanings
are indicated on 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 "SCI" (obtained via (?MODE?), SHIFT, C) - and either Mode 2 (for 1-variable statistics) or Mode 3 (for 2-variable statistics)
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:
Can someone help me with notes on viewing/correcting data?
Press (?MODE?), SHIFT, C (for "SCI mode) if
necessary, then press MODE, 2 for 1-variable statistics. Be sure memory
is cleared.
Enter the first value, Press M+[DATA} to add the number to the memory, enter
the second value, press M+[DATA], etc.
Press (?MODE?), SHIFT, C (for "SCI mode) if
necessary, then press MODE, 2 for 1-variable statistics. Be sure memory
is cleared.
Enter the first value, Press X (multiplication symbol), enter the frequency,
press M+[DATA] to put into memory, enter the second value,press X, second
frequency, press M+[DATA], etc.
Press (?MODE?), SHIFT, C (for "SCI mode) if
necessary, then press MODE, 3 for linear regression mode. Be sure memory
is cleared.
Enter the first x-value, press [x0, y0],
enter y-value, press M+[DATA] to enter the pair into memory, enter the nextt
x-value, press [x0,
y0], enter
y-value, press M+[DATA] to enter the pair into memory, etc.
Press MODE, 2 to get1-variable mode .
For mean (xbar) press SHIFT, 1 [x-bar], for standard deviation, press SHIFT,
3 [xsigman-1], for sum of x's press RCL, 2 [Sum x], for sum of x-squareds
press RCL, 1 [Sum x^2], for count (n) press RCL, 3 [n].
Press MODE, 3 to getlinear regression mode.
For intercept press SHIFT, 7 [A], for slope press SHIFT, 8[B], for correlation
coefficient press SHIFT, 9[r]
This calculator uses the form y = A + Bx for the regression line, but does
not [I believe] remind you. [You might want to write on your calculator,
or on the inside of the cover, something like "A = int, B = slope"
to remind you]
Errors or questions? Please let me know: cpeltier@saintmarys.edu
Last update 7/20/98