Radio Shack TRS-80 PC-3 Owner's Manual page 199

The mean and standard deviation of Yare computed with the same formulas. These quantities are then used to calculate the
correlation coefficient between the two variables using the formulas:
S f P S
f X *
Y
(Sum of X)
*
(Sum of Y)
um
0
roductsx,y = um
0 -
N
Correlation x,y
Sum of Products(x,y)
.J
(Sum of Squares x )
*
(Sum of Squares y )
Finally the program computes the coefficients for the linear regression equation using the formulas:
Sum of Productsx,y
Sum of Squares y
a = Meany - (b x . y
*
Mean x )
The coefficients are then shown in the regression equation:
Y=a+bx.yX
Relationship of Two Variables Program
10: A
=
0, B
=
0, C
=
0, 0
=
0,
v =
0
20: INPUT "NUMBER OF OBSERV.? "; N
30:
DIM
X(NI, Y(N)
40:WAIT48
50: PAUSE "ENTER "; N;" PAIRS OF OBS:'
Initialize variables to accumulate sums
Get number of observations
Allocate arrays to hold observations
Set 3/4 second wait for prompts during data entry
Prompt start of data entry
199