Texas Instruments TI-89 Manual Book page 481

LnReg
MATH/Statistics/Regressions menu
LnReg list1, list2
Calculates the logarithmic regression and
updates all the system statistics variables.
All the lists must have equal dimensions
except for
represents xlist.
list1
represents ylist.
list2
represents frequency.
list3
represents category codes.
list4
represents category include list.
list5
Note:
list1
name or c1–c99 (columns in the last data
variable shown in the Data/Matrix Editor).
does not have to be a variable name and
list5
cannot be c1–c99.
Local
CATALOG
Local var1[, var2] [, var3] ...
Declares the specified
Those variables exist only during evaluation
of a program or function and are deleted
when the program or function finishes
execution.
Note: Local variables save memory because
they only exist temporarily. Also, they do not
disturb any existing global variable values.
Local variables must be used for
and for temporarily saving values in a multi-
line function since modifications on global
variables are not allowed in a function.
Lock
CATALOG
Lock var1[, var2] ...
Locks the specified variables. This prevents
you from accidentally deleting or changing
the variable without first using the unlock
instruction on that variable.
In the example to the right, the variable L1 is
locked and cannot be deleted or modified.
Note: The variables can be unlocked using
the Unlock
464 Appendix A: Functions and Instructions
[ ]
, [list3] [, list4, list5]
.
list5
through must be a variable
list4
as local variables.
vars
For
command.
In function graphing mode:
{1,2,3,4,5,6,7,8}! L1 ¸
{1,2,2,3,3,3,4,4}! L2 ¸
LnReg L1,L2 ¸
ShowStat ¸
¸
Regeq(x)"y1(x) ¸
NewPlot 1,1,L1,L2 ¸
¥ %
Program listing:
:prgmname()
:Prgm
:Local x,y
:Input "Enter x",x
:Input "Enter y",y
:Disp xù y
:EndPrgm
Note: x and y do not exist after the
program executes.
loops
{1,2,3,4}! L1 ¸
Lock L1 ¸
DelVar L1 ¸
Error: Variable is locked or protected
{1 2 3 ...}
{1 2 2 ...}
Done
Done
Done
{1,2,3,4}
Done