Number of subjects using category labels (N 1 = 15) | Average size of category (N 2 = 15) | Number of problems accounted for (N = N 1 × N 2 = 225) | Number of problems wrongly accounted for (N* = 225) | Number of problems correctly accounted for (N C = N − N*) | |
---|---|---|---|---|---|
Springs | 12 | 3.1 | 37 | 2 | 35 |
Free fall, etc. | 9 | 4.1 | 37 | 2 | 35 |
Collision | 12 | 2.0 | 24 | 0 | 24 |
Circular motion | 12 | 1.9 | 23 | 1 | 22 |
Acceleration | 3 | 5.7 | 17 | 1 | 16 |
Strings | 7 | 2.0 | 14 | 0 | 14 |
Inclined planes | 5 | 2.2 | 11 | 0 | 11 |
Balance | 5 | 2.4 | 12 | 4 | 8 |
Object only | 1 | 5.0 | 5 | 0 | 5 |
Friction | 3 | 1.7 | 5 | 0 | 5 |
Second law | 2 | 2.5 | 5 | 2 | 3 |
Pulleys | 1 | 2.0 | 2 | 0 | 2 |
Balance of energies | 1 | 4.0 | 4 | 2 | 2 |
Motion of weight | 1 | 2.0 | 2 | 0 | 2 |
Energy of falling object | 1 | 3.0 | 3 | 2 | 1 |
Linear uniform motion | 1 | 1.0 | 1 | 0 | 1 |
Simple harmonic motion | 1 | 1.0 | 1 | 0 | 1 |
Terminal velocity | 1 | 1.0 | 1 | 0 | 1 |
Internal force | 1 | 5.0 | 5 | 5 | 0 |
Others | 1 | 15 | 15 | 2 | 13 |