Chapter 13: Inferential Statistics and Distributions
236
LinRegTTest
LinRegTTest
(linear regression
t
test; item
F)
computes a linear regression on the given data and a
t
test on the value of slope
b
and the correlation coefficient
r
for the equation
y
=
a
+
b
x. It tests the
null hypothesis H
0
:
b
=0 (equivalently,
r
=0) against one of the alternatives below.
•
H
a
:
bƒ
0 and
rƒ
0 (
b
&
r
:
ă
0
)
•
H
a
:
b
<0 and
r
<0 (
b
&
r
:<0
)
•
H
a
:
b
>0 and
r
>0 (
b
&
r
:>0
)
The regression equation is automatically stored to
RegEQ
(
VARS Statistics EQ
secondary menu). If
you enter a Y= variable name at the
RegEQ:
prompt, the calculated regression equation is
automatically stored to the specified Y= equation. In the example below, the regression equation is
stored to
Y1
, which is then selected (turned on).
In the example:
L3={38, 56, 59, 64, 74}
L4={41, 63, 70, 72, 84}
When
LinRegTTest
is executed, the list of residuals is created and stored to the list name
RESID
automatically.
RESID
is placed on the
LIST NAMES
menu.
Note:
For the regression equation, you can use the fix-decimal mode setting to control the number
of digits stored after the decimal point (Chapter 1). However, limiting the number of digits to a
small number could affect the accuracy of the fit.
Input:
Calculated
results:
