54 Section 4: Statistics Functions
Example: Calculate the standard deviation about the mean calculated
above.
Keystrokes Display
| S
31.62
Standard deviation about the
mean nitrogen application, .
®
1.24
Standard deviation about the
mean grain yield, .
Linear Regression
Linear regression is a statistical method for finding a straight line that
best fits a set of two or more data pairs, thus providing a relationship
between two variables. By the method of least squares, ´ L will
calculate the slope, A, and y-intercept, B, of the linear equation:
y = Ax + B
1.
Accumulate the statistics of your data using the z key.
2.
Press ´ L. The y-intercept, B, appears in the display (X-
register). The slope, A, is copied simultaneously into the Y-register.
3.
Press ® to view A. (As is the case with the functions ’ and
S, L causes the stack to lift two registers if it’s enabled, one if
not.)
T
t
y
y
Z
z
x
x
Y
y
A
slope
B
y-intercept
X
x
B
y-intercept
A
slope
Keys:
´
L
®
The slope and y-intercept of the least squares line of the accumulated
data are calculated using the equations shown in Appendix A.
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