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2.4 ³»Àû ÇÕÄ¡µµ ¹æ¹ý(internal consistency method)
¾Õ¿¡¼ ¼³¸íÇÑ ¹ÝºÐ¹ýÀÇ °áÁ¡Àº ½ÇÁ¦ÀÇ ÀÚ·áºÐ¼®¿¡ À־ ¾î¶»°Ô ½ÃÇèÁö¸¦ µÎ ºÎºÐÀ¸·Î ³ª´©´À³Ä¿¡ µû¶ó ½Å·Úµµ ¥ñÀÇ ÃßÁ¤Ä¡°¡ ´Þ¶óÁø´Ù´Â »ç½ÇÀÌ´Ù. ÀÌ¿¡ ´ëÇÑ ´ë¾ÈÀ¸·Î¼ ´ÙÀ½°ú °°Àº »ý°¢À» ÇÒ ¼ö ÀÖ´Ù. X1,...XN À» °¢ ¹®Ç× Á¡¼ö¶ó°í Çϰí X1`,...XN`¸¦ µ¿ÇüÀÇ ¹®Ç×Á¡¼ö¶ó°í ÇÑ´Ù¸é(Áï, ¹®Ç× 1,...,N, 1`,....N`ÀÌ ¹®Ç×µéÀÇ ÀüüÁý´ÜÀ¸·ÎºÎÅÍÀÇ È®·üÇ¥º»À̶ó¸é), µîºÐ»ê¼º(equal variances)°ú µî°øºÐ»ê¼º(equal covariances)ÀÇ °¡Á¤ÇÏ¿¡¼
Cov(X1 + .... + XN , X1` + .... + XN`) = N2¥ò12
Var(X1 + .... + XN)=Var(X1` + .... + XN`) = N¥ò2 + N(N-1)¥ò12
ÀÌ´Ù. ¿©±â¼ ¥ò12 = Cov(Xi,Xj), ¥ò2 = Var(Xi)ÀÌ´Ù. ÇÑÆí
Cov(X1 + .... + XN , X1` + .... + XN`) =
{Var(X1 + .... + XN) - ¥Ò Var(Xi)} N/(N-1)
ÀÌ µÈ´Ù. µû¶ó¼ ½Å·Úµµ´Â
¥ñ = Corr(X1 + ... + XN , X1` + ... + XN`)
= [{Var(X1 + .. + XN) - ¥Ò Var(Xi)} N/(N-1)] / Var(X1 + .. + XN)
= N/(N-1) {1- ¥ÒVar(Xi)/Var(¥ÒXi)}
À¸·Î Ç¥ÇöµÈ´Ù. ÀÌ °ø½ÄÀ» CronbachÀÇ Al¡¦(»ý·«)
Âü°í¹®Çå
1. ±è»ó°â(1988) ⌈¼±Áö¿øÁ¦¿Í ÈÄÁö¿øÁ¦ ÇÏ¿¡¼ÀÇ ÀÔÇлýµéÀÇ ÇзÂÂ÷¿¡ °üÇÑ ¿¬±¸⌋. °í·Á´ëÇб³ ´ëÇпø Åë°èÇаú ¼®»çÇÐÀ§ ³í¹®.
2. ½ÅÃæ·Ä(1990) ¡°SAS ¾ð¾îÀϹݡ±, ⌈SAS¸¦ ÀÌ¿ëÇÑ Åë°è Workshop⌋. °í·Á´ëÇб³ Åë°è¿¬±¸¼Ò Æí.
3. ÀÌÁ¾¼º(1985) ⌈Çൿ°úÇבּ¸¸¦ À§ÇÑ ÃøÁ¤ÀÌ·ÐÀÇ ±âÃÊ⌋. Áß¾ÓÀû¼ºÃâÆÇ»ç. (Mary J. Allen and Wendy M. YenÀÇ Introduction to Measurement TheoryÀÇ Æí¿ª)
4. Carmines, E. G. and Zeller, R.A.(1979) Reliability and Validity Assessment. Series : Quantitative Applications in the Social Sciences No. 17. Sage Publications, Beverly Hills.
5. Cronbach,L.J. (1971) `Test Validation,` in Educational Measurement, 2nd Edition(Edited by R. L. Thorndike). American Council on Education, Washington, D.C.(Chapter 14)
6. Norusis,M.J.(1988) SPSS/PC+ Advanced Statistics, Version 2 Edition. SPSS Inc.,Chicago.
7. Stanley,J.C.(1971) ¡°Reliablity,¡± in Educational Measurement, 2nd Edition (Edited by R.L. Thorndike). American Council on Education, Washington,D.C.(Chapter 13)