Table 5 Pre‐ and post‐test means and gain of sum scores on knowledge of plant managers on whole‐body vibration (WBV) and company policy on WBV control.

	Experimental group (n = 5)	Control group (n = 9)
	Mean sum (SD)	Mean sum (SD)
Knowledge
Pretest mean M1	10.0 (0.7)	10.9 (0.8)
Post‐test mean M2	10.4 (1.5)	9.9 (1.5)
Gain score M2‐M1	0.4 (1.3)	−1.0 (1.7)*
Company policy on WBV
Pretest mean M1	4.4 (1.5)	5.0 (1.6)
Post‐test mean M2	8.6 (1.9)	6.8 (2.6)
Gain score M2‐M1	4.2 (2.3)	1.8 (1.7)**

*p for difference in gain score =  0.08, Mann‐Whitney U test, one‐tailed **p = 0.02, Mann‐Whitney U test, one‐tailed.