HP -10C Owner's Handbook Manual page 50

48 Section 3: Numeric Functions
production (a "known" x-value) for 1977 and presses ´j. Because the
correlation coefficient for Voltz's data is automatically included in the
calculation, she can view how closely her data it a straight line by simply
pressing ® after the ŷ prediction appears in the display.
Keystrokes
7.142
´j
®
Conversely, suppose Voltz wishes to estimate the electrical output should there
be a future drop in coal production to 1.800 billion metric tons.
Keystrokes
1.8
´ª
®
Display
7.142
2.005
0.921
Display
1.8
5.951
0.921
Voltz's estimate of 1977
electrical output.
Predicted coal
production for 1977.
The original data closely
approximate a straight
line.
Hypothetical future coal
production.
Predicted electrical
output for that year.
Again, the correlation
coefficient for the
original data.