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+bx. It tests the
null hypothesis H
0
: b=0 (equivalently, r=0) against one of the alternatives below.
•H
a
: bƒ0 and rƒ0 (b & r:ă0)
•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:
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