Texas Instruments PLUS TI-89 - Manual (Page 534)

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}) ¸
añ -aø (b+c)+bñ -bø c+cñ
3
variance({1,2,5,л 6,3,л 2}) ¸
31/2
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 ¸
when(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+3,5ì x^2) ¸