Texas Instruments TI-89 Guide Book

Appendix A: Functions and Instructions 517
8992APPA.DOC TI-89 / TI-92 Plus: Appendix A (US English) Susan Gullord Revised: 02/23/01 1:48 PM Printed: 02/23/01 2:21 PM Page 517 of 132
variance()
MATH/Statistics menu
variance(
list
[
, freqlist
]
)
⇒
expression
Returns the variance of
list
.
Each
freqlist
element counts the number of
consecutive occurrences of the
corresponding element in
list
.
Note:
list
must contain at least two elements.
variance({a,b,c})
¸
a
ñ
-a
ø
(b+c)+b
ñ
-b
ø
c+c
ñ
3
variance({1,2,5,
ë
6,3,
ë
2})
¸
3
1/
2
variance({1,3,5},{4,6,2})
¸
68
/
33
variance(
matrix1
[
, freqmatrix
]
)
⇒
matrix
Returns a row vector containing the variance
of each column in
matrix1
.
Each
freqmatrix
element counts the number
of consecutive occurrences of the
corresponding element in
matrix1
.
Note:
matrix1
must contain at least two
rows.
variance([1,2,5;
ë
3,0,1;
.5,.7,3])
¸
[4.75 1.03 4]
variance([L1.1,2.2;3.4,5.1;
L2.3,4.3],[6,3;2,4;5,1])
¸
[3.91731,2.08411]
when()
CATALOG
when(
condition
,
trueResult
[,
falseResult
]
[,
unknownResult
]
)
⇒
expression
Returns
trueResult
,
falseResult
, or
unknownResult
, depending on whether
condition
is true, false, or unknown. Returns
the input if there are too few arguments to
specify the appropriate result.
Omit both
falseResult
and
unknownResult
to
make an expression defined only in the
region where
condition
is true.
when(x<0,x+3)|x=5
¸
w
h
en
(
x<0,3+x
)
Use an
undef
falseResult
to define an
expression that graphs only on an interval.
ClrGraph
¸
Graph when(x‚
ë
p and
x<0,x+3,undef)
¸
Omit only the
unknownResult
to define a two-
piece expression.
Graph when(x<0,x+3,5
ì
x^2)
¸

Texas Instruments TI-89 Specifications

General

Display size (HxV)	100 x 160 mm
Memory type	639K FLASH ROM, 188K bytes RAM
Compatible operating systems	Operating System 2.09
Battery type	AAA