Table 1

Number of respondents and chance (p values, below) to end up in the sample per sample stratum; the number of non-respondents per exposure stratum are in parentheses

Kosten units	Distance in km					Total response	(non-respondents)
Kosten units	⩽5	>5–10	>10–15	>15–20	>20–25	Total response	(non-respondents)
×, noise-distance combination does not occur.
<20	33	595	766	750	543	2687	(45)
	0.05	0.01	0.01	0.01	0.01	0.01
⩾20–25	128	601	457	320	395	1901	(59)
	0.06	0.02	0.02	0.03	0.02	0.02
⩾25–30	104	736	513	602	421	2376	(51)
	0.05	0.03	0.07	0.13	0.17	0.06
⩾30–35	224	655	520	182	×	1581	(26)
	0.37	0.10	0.16	0.33		0.14
⩾35–40	138	802	341	55	×	1336	(44)
	0.46	0.26	0.43	0.40		0.30
⩾40–45	80	890	126	×	×	1096	(26)
	0.41	0.37	0.56			0.39
⩾45–50	47	528	6	×	×	581	(17)
	0.55	0.35	0.36			0.36
⩾50–55	47	179	4	×	×	230	(3)
	0.43	0.41	0.64			0.42
⩾55–60	9	11	×	×	×	20	(0)
	0.33	0.75				0.46
⩾60	4	×	×	×	×	4	(0)
	0.45					0.45
Total response	814	4997	2733	1909	1359	11812
(non-response)	(52)	(95)	(46)	(47)	(31)		(271)