Radio Shack TRS-80 PC-3 Owner's Manual page 198

961: DATA 28800,6138, .38
962: DATA 34100,8152, .41
963: DATA 44700, 12498,.49
964: OATA 60600, 20289, . 50
Relationship of Two Variables
The PC-3 Computer an excellent tool for making many small statistical tests. As an example of this capability, this program
calculates the basic tests which are often used to compare a series of paired observations. The program solicits the observations
which are entered in pairs. When there are an independent and a dependent variable, the dependent variable is X and the independ-
ent is Y. If the variables are independent, then simply assign one to X and one to Y.
The program loops through the observations and computes several quantities which are used to calculate the desired statistics.
These quantities are the Sum of X, the Sum of X
2
,
the Sum of Y, the Sum of y
2
,
and the Sum of X*Y. The mean of X is then
computed with the formula:
M
Sum of X
ean = - - - -
x
N
Where N is the number of observation pairs. The standard deviation of X is then calculated with these formu las:
(Sum of
X)2
Sum of Squares
x
= Sum of X
2
- - ' - - - - - -
N
" j
Sum of Squares
Standard Devlatlon
x
=
x
(N - 1)
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