Section 4: Using HP-41C Functions64
    1st
2nd
3rd
4th
5th
    10-Mile
10-Mile
10-Mile
10-Mile
10-Mile
    Run
Run
Run
Run
Run
Timing in Minutes 52.60
53.55
51.25
50.65
48.76
Using the following keystrokes, determine the average (mean) timing for the five runs. (Don’t be concerned quite yet how the Σ+ function works, it is covered in detail in section 6.) Place the HP-41C into USER mode by pressing USER. This lets you use the MEAN function that is assigned to the   key location.
Keystrokes Display    
USER   0.0000   Place the HP-41C in USER mode. All customized functions become active. Notice that the USER annunciator in the display is also turned on.
g CLΣ   0.0000    
52.6000 Σ+  1.0000    
53.5500 Σ+  2.0000    
51.5200 Σ+  3.0000    
50.6500 Σ+  4.0000    
48.7600 Σ+  5.0000    
MEAN (   )  MEAN   Press and hold the key for a moment. Notice how the HP-41C shows the name of the function assigned to that key location and not the name of the function printed on the key.
   51.3620   Joel ran an average of 51.3620 minutes in his five-mile runs (that’s about 5.1 minutes per mile); a pretty good pace for the marathon.
USER   51.3620   Takes the HP-41C out of USER mode. All normal key functions now become active on the keyboard.
The MEAN function remains assigned to the   key location in USER mode until you change the key assignment. This exciting feature of the HP-41C allows you to customize your calculator by assigning the functions you use the most to the USER mode keyboard. And you can always use the normal key functions by simply pressing USER again to place the HP-41C back into normal mode.