Texas Instruments TITANIUM TI-89 - Manual (Page 893)

Appendix A: Functions and Instructions 893
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;
L
2.3,4.3],[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‚ëp 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) ¸
Nest when() to define expressions that have
more than two pieces.
"
ClrGraph
¸ Done
Graph when(x<0,when(x<лp,
4щ sin(x),2x+3),5ì x^2) ¸