Page 168 - สถิติทางวิทยาศาสตร์สุขภาพ เพื่อการวิจัย

Ò= Ò error ·≈– Ú = Ú error

p - p = §«“¡µà“ߢÕߺ≈
T C
À¡“¬‡Àµÿ „™â Z „π Ÿµ√°√≥’∑’Ë°“√∑¥ Õ∫‡ªìπ·∫∫¥â“π‡¥’¬«
Ò
Z „π Ÿµ√°√≥’∑’Ë°“√∑¥ Õ∫‡ªìπ·∫∫ 2 ¥â“π
Ò/2

µ—«Õ¬à“ß∑’Ë 9.4

„π°“√»÷°…“‡æ◊ËÕª√–‡¡‘π«à“°“√∑’Ë·¡à‰¥â√—∫°“√¥Ÿ·≈¢≥–µ—Èߧ√√¿å “¡“√∂≈¥Õ—µ√“
°“√§≈Õ¥°àÕπ°”À𥉥âÀ√◊Õ‰¡à ®“°√“¬ß“πæ∫«à“À≠‘ß∑’ˉ¡à‰¥âΩ“°§√√¿å¡’Õ—µ√“°“√§≈Õ¥

°àÕπ°”Àπ¥ 20% ·≈–®“°°“√ª√–¡“≥¢Õß·æ∑¬å§“¥«à“·¡à∑’ˉ¥â√—∫°“√¥Ÿ·≈¢≥–µ—Èߧ√√¿å
“¡“√∂≈¥Õ—µ√“°“√§≈Õ¥°àÕπ°”Àπ¥‡À≈◊Õ 10%
®–‰¥â«à“ p §◊Õ 20% À√◊Õ 0.2 ·≈–§à“ p §◊Õ 10% À√◊Õ 0.1
C T
°”Àπ¥„Àâ H : ˆ = ˆ H : ˆ < ˆ
0 T C A T C
®“° p = 0.2 p = 0.1 §”π«≥§à“ p = (0.2 + 0.1)/2 = 0.15
C T
„Àâ Ò= 0.05 Æ Z = 1.65 (°“√∑¥ Õ∫¥â“π‡¥’¬«)
0.05
Õ”π“®°“√∑¥ Õ∫ = 80 Ú = 0.2 Æ Z = 0.84
0.2
2
21 65(. + 0 84. ) 0 15. ¥ 0 85.
¥
n/°≈ÿà¡= 2
(0.2 - 0.1)
= 158 §π
¥—ßπ—Èπ„π°“√∑¥ Õ∫¥—ß°≈à“«®–µâÕß„™â¢π“¥µ—«Õ¬à“ß°≈ÿà¡≈– 158 §π

„π°√≥’∑’Ë¡’º≈°“√»÷°…“‡∫◊ÈÕßµâπæ∫«à“«‘∏’°“√„À¡àÀ√◊Õ¬“„À¡à¡’º≈¥’°«à“‡¥‘¡·µà¬—ß
‰¡à¡’¢âÕ¡Ÿ≈√–∫ÿ«à“ p ‰¥âº≈¥’°«à“‡¥‘¡¡“°πâÕ¬‡æ’¬ß„¥ °“√°”À𥧫“¡µà“ߢÕߺ≈‡æ◊ËÕ
T
§”π«≥¢π“¥µ—«Õ¬à“ß„Àâª√–¡“≥«à“«‘∏’°“√„À¡à®–¥’°«à“«‘∏’°“√‡¥‘¡∑’Ë„™âÕ¬Ÿà√âÕ¬≈–‡∑à“„¥‡æ◊ËÕ
„™â§”π«≥§à“§«“¡µà“ߢÕߺ≈ ·≈–§à“§«“¡µà“ߢÕߺ≈∑’˧”π«≥‰¥â§«√¡’¢π“¥„À≠àæÕ∑’Ë®–¡’

§«“¡ ”§—≠„π°“√„™âß“π (clinical À√◊Õ scientific importance) µ—«Õ¬à“߇™àπ «‘∏’°“√√—°…“
∑’Ë„™âÕ¬Ÿà‡¥‘¡ (standard treatment) ¡’§à“ —¥ à«π¢Õß°“√À“¬ p = 0.7 ∂â“π—°«‘®—¬°”Àπ¥„Àâ
C
°“√√—°…“„À¡àµâÕߥ’°«à“‡¥‘¡√âÕ¬≈– 20 ®÷ß®–¡’§«“¡ ”§—≠„π°“√„™âß“π ®–§”π«≥§à“ p
T
”À√—∫𔉪§”π«≥¢π“¥µ—«Õ¬à“߉¥â¥—ßπ’È

p = 0.7 p ¡“°°«à“ p √âÕ¬≈– 20
C T C
07. ¥ 20
®–‰¥â«à“ p = 0.7 + = 0.84
T
100
®–‰¥â«à“ p = 0.7 ·≈– p = 0.84 ”À√—∫°“√§”π«≥µ—«Õ¬à“ß„π°“√»÷°…“
C T

9.5 °“√§”π«≥¢π“¥µ—«Õ¬à“߇æ◊ËÕ‡ª√’¬∫‡∑’¬∫ —¥ à«π√–À«à“ߪ√–™“°√ 2 °≈ÿà¡ 167

∫∑∑’Ë 9 167 29/7/09, 5:34 PM