Operation Manual

Appendix B: Reference Information 378
Appendix B:
Reference Information
Variables
User Variables
The TI-84 Plus C uses the variables listed below in various ways. Some variables are restricted to specific
data types.
The variables
A through Z and q are defined as real or complex numbers. You may store to them. The
TI-84 Plus C can update X, Y, R, q, and T during graphing, so you may want to avoid using these
variables to store nongraphing data.
The variables (list names)
L1 through L6 are restricted to lists; you cannot store another type of data to
them.
The variables (matrix names)
[A] through [J] are restricted to matrices; you cannot store another type
of data to them.
The variables
Pic1 through Pic9 and Pic0 are restricted to pictures; you cannot store another type of
data to them.
The variables
Image1 through Image9 and Image0 are restricted to Background Images, you cannot
store another type of data to them.
The variables
GDB1 through GDB9 and GDB0 are restricted to graph databases; you cannot store
another type of data to them.
The variables
Str1 through Str9 and Str0 are restricted to strings; you cannot store another type of
data to them.
Except for system variables, you can store any string of characters, functions, instructions, or variables to
the functions
Yn, (1 through 9, and 0), XnT/YnT (1 through 6), rn (1 through 6), u(n), v(n), and w(n)
directly or through the Y= editor. The validity of the string is determined when the function is evaluated.
Archive Variables
You can store data, programs or any variable from RAM to user data archive memory where they cannot
be edited or deleted inadvertently. Archiving also allows you to free up RAM for variables that may
require additional memory. The names of archived variables are preceded by an asterisk (*) indicating
they are in user data archive. Exception  4:Picture & Background... BACKGROUND menu does not
display the * even though Image Vars are stored only in Archive Mode.
System Variables
The variables below must be real numbers. You may store to them. Since the TI-84 Plus C can update
some of them, as the result of a ZOOM, for example, you may want to avoid using these variables to
store nongraphing data.
•
Xmin, Xmax, Xscl, @X, TraceStep, XFact, Tstep, PlotStart, nMin, and other window variables.
•
ZXmin, ZXmax, ZXscl, ZTstep, ZPlotStart, Zu(nMin), and other ZOOM variables.
The variables below are reserved for use by the TI-84 Plus C. You cannot store to them.
n, v, Sx, sx, minX, maxX, Gy, Gy
2
, Gxy, a, b, c, RegEQ, x1, x2, y1, z, t, F, c
2
, Ç, v1, Sx1, n1, lower, upper,
r
2
, R
2
and other statistical variables.
Statistics Formulas
This section contains statistics formulas for the Logistic and SinReg regressions, ANOVA, 2-SampÜTest,
and
2-SampTTest.