Page 91 - สถิติทางวิทยาศาสตร์สุขภาพ เพื่อการวิจัย

°“√ª√–¡“≥™à«ß§«“¡‡™◊ËÕ¡—Ëπ

s 2 p s 2 p
m - m =(x - x ) £ t +
1 2 1 2 a
( df ) n 1 n 2
2
µ—«Õ¬à“ß∑’Ë 5.2

„π°“√»÷°…“‡ª√’¬∫‡∑’¬∫ª√‘¡“≥‚ª√µ’π∑’Ë∫√‘‚¿§µàÕ«—π¢Õßπ—°‡√’¬π™—Èπª√–∂¡»÷°…“
„π™π∫∑¿“§Õ’ “π·≈–¿“§°≈“ß«à“¡’ª√‘¡“≥·µ°µà“ß°—πÀ√◊Õ‰¡à »÷°…“‚¥¬ ÿà¡ ”√«®

π—°‡√’¬π™—Èπª√–∂¡»÷°…“¿“§≈– 30 §π ∫—π∑÷°°“√∫√‘‚¿§Õ“À“√ 21 «—π æ∫«à“¡’ª√‘¡“≥
‚ª√µ’π∑’Ë∫√‘‚¿§¥—ßπ’È π—°‡√’¬π¿“§Õ’ “π x = 57 °√—¡ s = 9.9 °√—¡ π—°‡√’¬π¿“§°≈“ß
1 1
x = 61.9 °√—¡ s = 10.4 °√—¡ °“√ √ÿªº≈°“√»÷°…“∑”‰¥â¥—ßπ’È
2 2
°“√∑¥ Õ∫ ¡¡µ‘∞“π

¢—Èπ∑’Ë 1 H : m = m H : m π m
0 1 2 A 1 2
2
¢—Èπ∑’Ë 2 ¡¡µ‘„Àâª√‘¡“≥‚ª√µ’π∑’Ë∫√‘‚¿§¡’§«“¡·ª√ª√«π‡∑à“°—π s = s 2
1 2
x - x
„™â ∂‘µ‘ t= 1 2
2 2
s s
p p
+
n n
1 2
¢—Èπ∑’Ë 3 °”Àπ¥„Àâ Ò = 0.05
¢—Èπ∑’Ë 4 §”π«≥§à“ t

2 (30 - 1 ) .9 9 2 + (30 - ) 1 10 .4 2
s =
p 30 + 30 - 2

= 103.1
57 - 61 9 .
t= = -1.87
103 1 . 103 1 .
+
30 30
df = 30 + 30 - 2 = 58

®“°µ“√“ß 2 t = -1.87 ‰¥â§à“ P value > 0.025
(58)

¢—Èπ∑’Ë 5 §à“ P value > 0.025 ¡“°°«à“§à“ Ò/2 (0.025) º≈°“√∑¥ Õ∫‰¡àªØ‘‡ ∏

H · ¥ß«à“ª√‘¡“≥‚ª√µ’π∑’Ë∫√‘‚¿§µàÕ«—π¢Õßπ—°‡√’¬π™—Èπª√–∂¡»÷°…“¿“§Õ’ “π·≈–¿“§°≈“ß
0
‰¡à·µ°µà“ß°—π¥â«¬√–¥—∫π—¬ ”§—≠ 0.05

90 ∫∑∑’Ë 5 °“√‡ª√’¬∫‡∑’¬∫º≈≈—æ∏å∑’ˇªìπ¢âÕ¡Ÿ≈µàÕ‡π◊ËÕß

∫∑∑’Ë 5 90 29/7/09, 11:45 AM