Page 231 - สถิติทางวิทยาศาสตร์สุขภาพ เพื่อการวิจัย

2
Û = -2(LL - LL )
Beginning model(B) Ending model(E)
Likelihood B()
= -2ênÄ Â (‡æ√“– ên ≈∫°—π‡∑à“°—∫ ên À“√°—π)
Likelihood E()

„π°√≥’∑’Ë¡’µ—«·ª√Õ‘ √–‡æ’¬ßµ—«‡¥’¬« LL ®–‡ªìπ§à“ LL ‡¡◊ËÕ¡’§à“ a Õ¬Ÿà„πµ—«·∫∫
B
‡æ’¬ß§à“‡¥’¬« ·≈– LL ®–‡ªìπ§à“ LL ‡¡◊ËÕ¡’ a ·≈– b „πµ—«·∫∫ ®“°¢âÕ¡Ÿ≈µ—«Õ¬à“ß
E 1
2
c
-2LL = 160.68 ·≈– -2LL = 101.15 ¡’§à“ = 59.53 P value < 0.001 · ¥ß«à“
B E 1
µ—«·ª√∑’ˇæ‘Ë¡‡¢â“‰ª„πµ—«·∫∫∑”„Àâ§à“ LL ‡ª≈’ˬπ·ª≈ßÕ¬à“ß¡’π—¬ ”§—≠

16.3.2 §«“¡∂Ÿ°µâÕߢÕß°“√∑”π“¬

®“°µ—«·∫∫∑’ˉ¥â∂â“π—°«‘®—¬ “¡“√∂π”¢âÕ¡Ÿ≈Õ“¬ÿ®“°µ—«Õ¬à“ß¡“§”π«≥§à“ P ¥â«¬
¡°“√∑’Ë √â“ߢ÷Èπ ∂â“§à“ P ∑’˧”π«≥®“°µ—«·∫∫¡’§à“‡∑à“°—∫À√◊Õ¡“°°«à“ 0.5 ®–∑”π“¬

«à“‡ªìπ‚√§‡∫“À«“π ∂â“πâÕ¬°«à“ 0.5 ®–∑”π“¬«à“‰¡à‡ªìπ‚√§‡∫“À«“π º≈°“√§”π«≥
®“°µ—«·∫∫∑”𓬮”π«πºŸâ∑’Ë®–‡ªìπ‚√§‡∫“À«“π‰¥â¥—ßπ’È

®”π«π§π ®”π«π§π∑’ˇªìπ‚√§‡∫“À«“π
Õ“¬ÿ
∑—ÈßÀ¡¥ —߇°µ ∑”π“¬

42 30 1 1
51 22 1 3
60 14 6 5

66 17 10 9
72 9 6 6
74 16 13 12
85 12 10 11

√«¡ 120 47 47

∂â“π”º≈°“√∑”π“¬¡“‡∑’¬∫°—∫§à“∑’ˉ¥â®“°°“√ —߇°µ (observe) °Á®– “¡“√∂
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∂Ÿ°µâÕß ¥—ßπ’È

230 ∫∑∑’Ë 16 µ—«·∫∫≈Õ®‘ µ‘°

∫∑∑’Ë16 230 30/7/09, 1:37 PM