HP 15C Bedienungsanleitung PDF herunterladen (Seite 56)

56 Section 4: Statistics Functions

Linear Estimation. With the statistics accumulated, an estimated value for

y, denoted ŷ, can be calculated by keying in a proposed value for x and

pressing ´j.

An Estimated value for x (denoted



) can be calculated as follows:

Press ´L.

Key in the known y-value.

Press ® - ® ÷.

Correlation Coefficient. Both linear regression and linear estimation

presume that the relationship between the x and y data values can be

approximated by a linear function. The correlation coefficient, r, is a

determination of how closely your data fit a straight line. The range is -1  r

 1, with -1 representing a perfectly negative correlation and +1

representing a perfectly positive correlation.

Note that if you do not key in a value for x before executing ´j, the

number previously in the X-register will be used (usually yielding a

meaningless value for ŷ).

Example: What if 70 kg of nitrogen fertilizer were applied to the rice field?

Predict the grain      

the correlation coefficient is automatically included in the calculation, you

can view how closely the data fit a straight line by pressing ® after the

y prediction appears in the display.

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HP 15C Bedienungsanleitung Seite 56