The agreement between workers and within workers in regard to occupational exposure to mercury in dental practice assessed from a questionnaire and an interview

Table 4 Kappa statistics for the same answers in the questionnaire and the interview.

Question	N	Yes from interview	Yes from questionnaire	kappa	95% conf intervals
Yes-no have ever used copper amalgam	84	51	52	0.88	0.77-0.99
Yes-no have ever used a mortar	85	28	48	0.41	0.24-0.58
Yes-no have ever used a Dentomat	85	76	77	0.54	0.24-0.84

ISSN: 1745-6673