HP 50g Graphing Calculator - Manual (Page 578)

Page 18-11
Θ First, enter the two rows of data into column in the variable ΣDAT by using
the matrix writer, and function STO Σ.
Θ To access the program
3. Fit data..
, use the following keystrokes:
‚Ù˜˜@@@OK@@@ The input form will show the current ΣDAT, already
loaded. If needed, change your set up screen to the following parameters
for a linear fitting:
Θ To obtain the data fitting press @@OK@@. The output from this program, shown
below for our particular data set, consists of the following three lines in RPN
mode:
3: '0.195238095238 + 2.00857142857*X'
2: Correlation: 0.983781424465
1: Covariance: 7.03
Level 3 shows the form of the equation. In this case, y = 0.06924 + 0.00383 x.
Level 2 shows the sample correlation coefficient, and level 1 shows the
covariance of x-y.
Definitions
For a sample of data points (x,y), we define the sample covariance as
The sample correlation coefficient for x,y is defined as
.
) )( (
1
1
1
y y x x
n
s
i
n
i
i xy
− −
−
=
∑
=
y x
xy
xy s s
s
r
⋅
=