| N | Mean | SD | Minimum | Maximum |
High-R & D firms | 118 | 0.0591 | 0.0371 | 0.0179 | 0.1909 |
Low-R & D firms | 170 | 0.1301 | 0.0349 | 0.0202 | 0.1996 |
T-test of mean difference | t = −2.76 (p < 0.01) |