Table 11.

Sample size for powering trials using WURSS-21 and WURSS-44

	one-tailed α = 0.005 (two-tailed α = 0.01)			one-tailed α = 0.025 (2-tailed α = 0.05)			one-tailed α = 0.05 (two-tailed α = 0.10)
β =	0.05	0.10	0.20	0.05	0.10	0.20	0.05	0.10	0.20
Power	95%	90%	80%	95%	90%	80%	95%	90%	80%
Sample size per group needed to detect day-to-day MID (using Guyatt's responsiveness coefficient)
WURSS-21	72	60	47	52	43	32	44	35	25
WURSS-44	64	53	42	47	38	28	39	31	22
WURSS-21 – Sample size per group needed to detect between group AUC differences of:
10%	2348	1961	1540	1712	1385	1035	1426	1129	815
20%	578	483	379	421	341	255	351	278	201
30%	259	217	171	189	153	115	157	124	90
40%	147	123	97	107	87	65	89	71	51
50%	95	80	63	69	56	42	57	46	33
WURSS-44 – Sample size per group needed to detect between group AUC differences of:
10%	2787	2328	1828	2033	1644	1228	1693	1340	967
20%	697	583	458	508	411	307	423	335	242
30%	312	261	205	227	184	138	189	150	108
40%	176	147	116	128	104	78	107	85	61
50%	113	95	75	82	67	50	69	55	40