TM 5-6675-322-14
Keystrokes
79
+
94
68
86
82
78
83
89
D i s p l ay
1.0000
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 h e
key.
Display shows number of scores
entered so far.
2.0000
3.0000
4.0000
5.0000
6.0000
7.0000
8.0000
Last score in sample.
7.8365
Standard deviation of test
scores.
( 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 ng
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 ip
between two variables.
( a ) T o 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
points
using
the
key.
Then press L.R.
(b)
When
L.R.
if
pressed:
The contents of the stack registers are lifted just as they are when you
p r e ss
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 the
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 ) T o u s e v a l u e f o r A o r t o b r i n g i t i n t o d i s p l a y e d X - r e g i s t e r , s i m p l y
s h i f t s t a c k c o n t e n t s w i t h t h e
key.
Example:
An oil company wishes to know the slope and y-intercept of a least
squares line for the consumption of motor fuel in the United States against time
since 1945.
It knows the data given in the table.
3-32
