Page 187 - สถิติทางวิทยาศาสตร์สุขภาพ เพื่อการวิจัย

°“√ ÿà¡·∫∫°≈ÿà¡®–¡’§«“¡·ª√ª√«π¢Õß°“√ ÿà¡¡“°°«à“°“√ ÿà¡·∫∫ßà“¬ π—Ëπ§◊Õ
§«“¡·ª√ª√«π¢Õß°“√ ÿà¡·∫∫°≈ÿà¡ (V ) ‡∑à“°—∫§«“¡·ª√ª√«π¢Õß°“√ ÿà¡·∫∫ßà“¬
CLUS
(V ) √«¡°—∫§«“¡·ª√ª√«π√–À«à“ß°≈ÿà¡ (V ) ¥—ß ¡°“√
SR B

V =V + V
CLUS SR B
—¥ à«π§«“¡·ª√ª√«π¢Õß°“√ ÿà¡∑—Èß 2 ·∫∫‡√’¬°«à“ design effect

design effect (D) = V /V
CLUS SR

‡¡◊ËÕ§«“¡·ª√ª√«π‡æ‘Ë¡¢÷Èπ¢π“¥¢Õßµ—«Õ¬à“ß®–„À≠à¢÷Èπ‡ªìπ —¥ à«π°—π‚¥¬µ√ß
¥—ßπ—Èπ‡¡◊ËÕ∑√“∫«à“§«“¡·ª√ª√«π‡æ‘Ë¡¢÷Èπ°’ˇ∑à“°Á®– “¡“√∂§”π«≥¢π“¥µ—«Õ¬à“ß∑’ˇæ‘Ë¡¢÷Èπ‰¥â
∑”„Àâ°“√§”π«≥¢π“¥µ—«Õ¬à“ߢÕß°“√ ÿà¡·∫∫°≈ÿࡧ”π«≥‰¥â®“° Ÿµ√§”π«≥¢π“¥

µ—«Õ¬à“ߥ⫬«‘∏’°“√ ÿà¡·∫∫ßà“¬·≈⫪√—∫¥â«¬§à“ design effect ¥—ßπ’È

n =n Ó D
CLUS SR

¢π“¥¢Õß design effect ®–·ª√‰ªµ“¡ªí≠À“·≈– ¿“æ¢ÕßÀ¡Ÿà∫â“π (°≈ÿà¡) ∂â“
§«“¡·µ°µà“ß√–À«à“ß°≈ÿࡉ¡à¡’‡≈¬ design effect (V /V ) ®–¡’§à“‡∑à“°—∫ 1 ∑”„Àâ
CLUS SR
¢π“¥µ—«Õ¬à“ß ”À√—∫°“√ ÿà¡·∫∫°≈ÿà¡®–‡∑à“°—∫¢π“¥µ—«Õ¬à“ߢÕß°“√ ÿà¡·∫∫ßà“¬ §à“ design

effect À“‰¥â®“°°“√»÷°…“∑’˺à“π¡“ ‡™à𠧫“¡§√Õ∫§≈ÿ¡¢Õß°“√‰¥â√—∫«—§´’π = 1.39
Õ—µ√“°“√√Ÿâ®—° º ./Õ ¡. ¢Õߪ√–™“™π = 1.57 Õ—µ√“°“√ªÉ«¬‚√§Õÿ®®“√–√à«ß„π™à«ß 2
—ª¥“Àå = 6 ‡ªìπµâπ

„π°√≥’∑’ˉ¡à “¡“√∂À“§à“ design effect ®“°√“¬ß“π π—°«‘®—¬Õ“®ª√–¡“≥§à“ design
effect ‚¥¬æ‘®“√≥“®“°§«“¡·µ°µà“ß√–À«à“ß°≈ÿà¡¢Õßµ—«·ª√º≈∑’˵âÕß°“√»÷°…“«à“¡’¡“°
πâÕ¬‡æ’¬ß„¥ ‚¥¬ª°µ‘∂Ⓣ¡à„™à‡√◊ËÕߢÕß°“√√–∫“¥¢Õß‚√§ design effect ®–‰¡à‡°‘π 2

µ—«Õ¬à“ß®“°ªí≠À“‡√◊ËÕß°“√»÷°…“ “‡Àµÿ°“√‡ ’¬™’«‘µ¢Õß∑“√°„π®—ßÀ«—¥¢Õπ·°àπ
¢π“¥¢Õßµ—«Õ¬à“ß∑’˧”π«≥‚¥¬«‘∏’ ÿà¡Õ¬à“ßßà“¬‰¥â‡∑à“°—∫ 1,825 §π ∂â“„π°“√»÷°…“µâÕß°“√
ÿà¡·∫∫°≈ÿà¡®–µâÕ߇æ‘Ë¡®”π«πµ—«Õ¬à“ß‚¥¬°“√ª√—∫¢π“¥µ—«Õ¬à“ߥ⫬¢π“¥¢Õß design effect

∂â“°”Àπ¥„Àâ§à“ design effect ¢ÕßÕ—µ√“°“√‡ ’¬™’«‘µ¢Õß∑“√°‡∑à“°—∫ 2 µ—«Õ¬à“ß∑—ÈßÀ¡¥∑’Ë
®–„™â ÿà¡·∫∫°≈ÿà¡ (n ) ®–‡ªìπ‡∑à“„¥
CLUS
n =n Ó D
CLUS SR
n = 1,825 Ó 2 = 3,650
CLUS
∂â“‚¥¬‡©≈’ˬ·≈â«„π·µà≈–À¡Ÿà∫â“π¡’À≠‘ßµ—Èߧ√√¿åªï≈–ª√–¡“≥ 20 §π
®”π«πÀ¡Ÿà∫â“πµ—«Õ¬à“ß∑—ÈßÀ¡¥ = 3,650/20 = 183 À¡Ÿà∫â“π

186 ∫∑∑’Ë 10 «‘∏’§”π«≥¢π“¥µ—«Õ¬à“ß„π°“√»÷°…“·∫∫µà“ßÊ

∫∑∑’Ë10 186 30/7/09, 9:19 AM