APPENDIX 435 
For each trial the exact time, number of balls successfully 
dropped, and the R. P. M. should be recorded. 
Rating: Point of reference for trial a is 60 successful attempts; 
b, 70; c, 50. In each case, the time is 120 seconds. Sample 
record, 91: a — 50; b — 64; c — 47. Formula I is applied 
to each record separately. In this case, the formula would 
work out as follows: — = .82; — = .91; — = .94. 
60 J 70 50 ^ 
Standards: Only approximate standards for this test have been 
developed. For the type of work described in Chapter X 
a minimum of .80 for fast machine operators, and .60 for 
slow machine operators was required.