Texas Instruments TI-73 EXPLORER - Manual (Page 148)

142
Chapter 7: Statistical Analyses
7307ENG.DOC CH 7, Statistical Analyses, English Julie Hewlett Revised: 07/29/98 12:07 PM Printed: 05/19/99
9:00 AM Page 142 of 22
5. View the line on the Graph
screen.
(
7
6. View the equation stored to
Y
2
, if desired.
&
LinReg(ax+b) LinReg(ax+b) - v ! 5 5
LinReg(ax+b)
(linear regression) fits the model equation
y=ax+b
to the data using a least-squares fit. It displays the value for
a
(slope) and
b
(y-intercept); when
DiagnosticOn
is set, it also
displays values for
r 2
(coefficient of determination) and
r
(correlation coefficient). The
DiagnosticOn
command is in the
CATALOG
(-|).You can execute
LinReg(ax+b)
from the
Graph screen, Home screen, or the Program editor.
It is also helpful to compare the slope of the line you draw
with
Manual-Fit
to the slope of the line the calculator calculates
with the
LinReg(ax+b)
command.
From the Home screen or the Program editor,
LinReg(ax+b)
accepts four optional arguments. Enter up to two list names,
XList and YList; a frequency list, freq; and an equation
variable, Yn. freq is the frequency of occurrence for each
corresponding data point in XList and YList. If freq is omitted,
all values are used once. If XList and YList are not specified,
the default list names are
L 1
and
L 2
. To access
Y
n
variables,
press - }
2:Y-Vars
.
LinReg(ax+b)
[XList,YList,freq,Yn]
The Med-Med
line
The Manual-Fit line,
Y
1
(previous section).
Y
3
and Y
4
may vary.