146 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 146 of 22
6. View the equation stored to
Y1, if desired.
&
ExpReg ExpReg -
v
!
7 7
ExpReg (exponential regression) fits the model equation y=abx
to the data using a least-squares fit and transformed values x
and ln(y). It displays values for a and b; when DiagnosticOn is
set, it also displays values for r2 (coefficient of determination)
and r (correlation coefficient). The DiagnosticOn command is in
the CATALOG (- |). You can execute ExpReg from the
Graph screen, the Home screen, or the Program editor.
From the Home screen or the Program editor, ExpReg 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 L1 and L2. To access Yn variables, press - } 2.
ExpReg [XList,YList,freq,Yn]
Graph a scatter plot for L1 and L2, where L1={1,3,4,5,5,7,8,9} and
L2={1,4,2,3,4,6,7,9}, and use ExpReg to draw the exponential
regression curve through the points.
1. Set Decimal Notation mode
to 2, if desired.
.#"""b
³
Y
2
, Y3, and Y4
may vary.