Statistics for Six Sigma Made Easy

D.5. Simplified F Table (95% Confidence)

For comparing sigma from two samples (sizes = n₁ and n₂) (sample sizes equal within 20%).

If calculated F_t value exceeds the table value, assume difference.

n	F	n	F	n	F
6	5.05	26	1.96	60	1.54
7	4.28	27	1.93	70	1.49
8	3.79	28	1.90	80	1.45
9	3.44	29	1.88	100	1.39
10	3.18	30	1.86	120	1.35
11	2.98	31	1.84	150	1.31
12	2.82	32	1.82	200	1.26
13	2.69	33	1.80	300	1.21
14	2.58	34	1.79	400	1.18
15	2.48	35	1.77	500	1.16
16	2.40	36	1.76	750	1.13
17	2.33	37	1.74	1000	1.11
18	2.27	38	1.73	2000	1.08
19	2.22	39	1.72
20	2.17	40	1.70
21	2.12	42	1.68
22	2.08	44	1.66
23	2.05	46	1.64
24	2.01	48	1.62
25	1.98	50	1.61