TM 5-6675-321-14
Keystrokes
79
D
D i s p l ay
1.0000
94
2.0000
F i r s t s c o r e i s e n t e r e d.
Since this problem involves
only one variable, y-value
does not have to be entered
i n t o Y - r e g i s t e r u s i n g t he
Display shows number of scores
entered so far.
68
3.0000
86
4.0000
82
5.0000
78
6.0000
83
7.0000
89
8.0000
Last score in sample.
7.8365
Standard deviation of test
s c o r e s.
( 5 ) L i n e a r r e g r e s s i o n . L i n e a r r e g r e s s i o n i s a s t a t i s t i c a l m e t h o d f o r f i n d i n g
a s t r a i g h t l i n e t h a t b e s t f i t s a s e t o f d a t a p o i n t s,
t h u s p r o v i d i n g a r e l a t i o n s h i p
between two variables.
( a ) TO u s e t h e l i n e a r r e g r e s s i o n f u n c t i o n , f i r s t k e y i n a s e r i e s o f d a ta
p o i n t s u s i n g t h e n k e y . T h e n p r e s s E L . R .
( b ) W h e n ~ L . R . i f p r e s s e d :
The contents of the stack registers are lifted just as they are when you
p r e s s E@ B.
The slope (A) of the least squares line of the data is available in the
Y - r e g i s t e r o f t h e s t a c k.
The y-intercept (B) of the least squares line of the data appears in
d i s p l a y e d X - r e g i s t e r o f t h e s t a c k.
(c) To use value for A or to bring it into displayed X-reqister, simply
s h i f t s t a c k c o n t e n t s w i t h t he
~
k e y .
Example:
An oil company wishes to know the slope and y-intercept of a
s q u a r e s f o r t h e c o n s u m p t i o n o f m o t o r f u e l i n t h e U n i t e d S t a t e s a g a i n st
since 1945.
It knows the data given in the table .
the
l e a s t
time
6-32