{"id":2004,"date":"2019-10-06T06:02:06","date_gmt":"2019-10-05T21:02:06","guid":{"rendered":"http:\/\/141.164.34.82\/?p=2004"},"modified":"2019-10-06T06:04:58","modified_gmt":"2019-10-05T21:04:58","slug":"%eb%ac%b8%ed%95%ad%ed%8a%b9%ec%84%b1%ec%9d%98-%eb%b6%88%eb%b3%80%ec%84%b1","status":"publish","type":"post","link":"http:\/\/ds.sumeun.org\/?p=2004","title":{"rendered":"\ubb38\ud56d\ud2b9\uc131\uc758 \ubd88\ubcc0\uc131"},"content":{"rendered":"

\ubb38\ud56d\ubc18\uc751\uc774\ub860: \ubb38\ud56d\ud2b9\uc131\uc758 \ubd88\ubcc0\uc131<\/h2>\n

\ub2e4\uc74c\uc740 “\uc608\ube44\uad50\uc0ac\ub97c \uc704\ud55c \uad50\uc721\ud3c9\uac00"\uc758 \uc77c\ubd80(p.168)\ub97c \ubc1c\ucdcc\ud55c \ub0b4\uc6a9\uc774\ub2e4.[1]<\/sup> <\/p>\n

"\ubb38\ud56d\ubc18\uc751\uc774\ub860\uc740 \ub2a5\ub825\uc774 \ub0ae\uc740 \ud53c\ud5d8\uc790 \uc9d1\ub2e8\uc5d0 \uac80\uc0ac\ub97c \uc2e4\uc2dc\ud574\ub3c4 \ub2a5\ub825\uc774 \ub192\uc740 \ud53c\ud5d8\uc790 \uc9d1\ub2e8\uc5d0 \uac80\uc0ac\ub97c \uc2e4\uc2dc\ud574\ub3c4 \ubb38\ud56d\ub09c\uc774\ub3c4, \ubb38\ud56d\ubcc0\ubcc4\ub3c4, \ubb38\ud56d\ucd94\uce21\ub3c4\ub97c \ucd94\uc815\ud558\uc600\uc744 \ub54c \uac12\uc774 \uac19\ub2e4\ub294 \uac83\uc774\ub2e4.”<\/strong><\/p>\n

[1]:<\/sup> \ube44\ub2e8 \uc774 \ucc45\ub9cc \uc544\ub2c8\uace0 \ub0b4\uac00 \ucc3e\uc544\ubcf8 \uac70\uc758 \ubaa8\ub4e0 \uad50\uc721 \ud3c9\uac00<\/strong> \ucc45\uc5d0\ub294 \ub3d9\uc77c\ud55c \ub0b4\uc6a9\uc774 \ub3d9\uc77c\ud558\uac8c (\ub4a4\uc5d0\uc11c \uc0b4\ud3b4\ubcf4\uaca0\uc9c0\ub9cc) \ubd80\uc2e4\ud55c \uc124\uba85\uc73c\ub85c \uc801\ud600 \uc788\uc5c8\ub2e4. Christine DeMars\uac00 \uc124\uba85\ud55c \ub0b4\uc6a9\uc744 \ubc1c\ucdcc\ud574\ubcf4\uc790. “In IRT, the item difficulty, \\(b\\) , is the same(invariant) across samples, up to linear transofrmation.”<\/p>\n

\uc774 \ub0b4\uc6a9\ub9cc \ubd10\uc11c\ub294 \uc624\ud574\uc758 \uc18c\uc9c0\uac00 \ub2e4\ubd84\ud55c \ub4ef \ud558\ub2e4. <\/p>\n

IRT\uc5d0\uc11c \ubaa8\uc9d1\ub2e8\uc758 \ub2a5\ub825 \ubd84\ud3ec\uc778 \ud45c\uc900 \uc815\uaddc \ubd84\ud3ec( \\(\\mathcal{N}(0,1)\\) )\uc740 \uc784\uc758\uc801\uc778 \uc124\uc815\uc774\ub2e4. \ub530\ub77c\uc11c \ud53c\ud5d8\uc790 \uc9d1\ub2e8\uc5d0 \ub530\ub77c \ubb38\ud56d\ub09c\uc774\ub3c4\uc640 \ubb38\ud56d\ubcc0\ubcc4\ub3c4\ub294 \ub2e4\ub974\uac8c \ucd94\uc815\ub41c\ub2e4.<\/p>\n

\ub2e4\uc74c\uc740 \ubaa8\uc9d1\ub2e8\uc758 \ub2a5\ub825 \ud3c9\uade0\uc774 0\uc778 \uacbd\uc6b0\uc640 1\uc778 \uacbd\uc6b0\uc5d0 \ubb38\ud56d \ub09c\uc774\ub3c4 \ucd94\uc815\uce58\uac00 \uc5b4\ub5bb\uac8c \ub2ec\ub77c\uc9c0\ub294\uc9c0\ub97c \ubcf4\uc5ec\uc900\ub2e4. <\/p>\n

library(mirt)\r\nlibrary(tibble)\r\nlibrary(dplyr)\r\nlibrary(ggplot2)\r\n\r\na = rep(1,10)\r\nd = rnorm(10)\r\nthA = matrix(rnorm(1000, mean=0), 1000, 1)\r\nthB = matrix(rnorm(1000, mean=1), 1000, 1)\r\nYA <- simdata(a=a, d=d, itemtype='2PL', Theta=thA)\r\nYB <- simdata(a=a, d=d, itemtype='2PL', Theta=thB)\r\n\r\nfitA <- mirt(YA, itemtype='2PL', model=1, SE=TRUE)\r\nfitB <- mirt(YB, itemtype='2PL', model=1, SE=TRUE)\r\n\r\ncfA <- coef(fitA, as.data.frame=TRUE)\r\ncfB <- coef(fitB, as.data.frame=TRUE)\r\n\r\ndat <- rbind(\r\n  cfA[grepl('d', rownames(cfA)), ,drop=FALSE] %>% \r\n    as_tibble %>% \r\n    rownames_to_column(var='item') %>% \r\n    mutate(group='A'),\r\n  cfB[grepl('d', rownames(cfB)), ,drop=FALSE] %>% \r\n    as_tibble %>% \r\n    rownames_to_column(var='item') %>% \r\n    mutate(group='B')\r\n) %>% \r\n  mutate(item = factor(item, levels=1:10))\r\n<\/code><\/pre>\n
## \r\nIteration: 1, Log-Lik: -5468.804, Max-Change: 0.19976\r\nIteration: 2, Log-Lik: -5449.417, Max-Change: 0.11241\r\nIteration: 3, Log-Lik: -5443.917, Max-Change: 0.06594\r\nIteration: 4, Log-Lik: -5442.263, Max-Change: 0.03871\r\nIteration: 5, Log-Lik: -5441.773, Max-Change: 0.02261\r\nIteration: 6, Log-Lik: -5441.625, Max-Change: 0.01267\r\nIteration: 7, Log-Lik: -5441.574, Max-Change: 0.00699\r\nIteration: 8, Log-Lik: -5441.563, Max-Change: 0.00401\r\nIteration: 9, Log-Lik: -5441.559, Max-Change: 0.00237\r\nIteration: 10, Log-Lik: -5441.558, Max-Change: 0.00129\r\nIteration: 11, Log-Lik: -5441.558, Max-Change: 0.00052\r\nIteration: 12, Log-Lik: -5441.558, Max-Change: 0.00034\r\nIteration: 13, Log-Lik: -5441.558, Max-Change: 0.00021\r\nIteration: 14, Log-Lik: -5441.558, Max-Change: 0.00014\r\nIteration: 15, Log-Lik: -5441.558, Max-Change: 0.00009\r\n## \r\n## \r\n## Calculating information matrix...\r\n## \r\nIteration: 1, Log-Lik: -5562.617, Max-Change: 0.16846\r\nIteration: 2, Log-Lik: -5552.706, Max-Change: 0.10277\r\nIteration: 3, Log-Lik: -5549.896, Max-Change: 0.06307\r\nIteration: 4, Log-Lik: -5548.948, Max-Change: 0.03148\r\nIteration: 5, Log-Lik: -5548.764, Max-Change: 0.01779\r\nIteration: 6, Log-Lik: -5548.709, Max-Change: 0.01030\r\nIteration: 7, Log-Lik: -5548.688, Max-Change: 0.00534\r\nIteration: 8, Log-Lik: -5548.684, Max-Change: 0.00353\r\nIteration: 9, Log-Lik: -5548.683, Max-Change: 0.00192\r\nIteration: 10, Log-Lik: -5548.682, Max-Change: 0.00063\r\nIteration: 11, Log-Lik: -5548.682, Max-Change: 0.00039\r\nIteration: 12, Log-Lik: -5548.682, Max-Change: 0.00024\r\nIteration: 13, Log-Lik: -5548.682, Max-Change: 0.00015\r\nIteration: 14, Log-Lik: -5548.682, Max-Change: 0.00009\r\n## \r\n## \r\n## Calculating information matrix...\r\n<\/pre>\n
pd = position_dodge(0.1)\r\ndat %>% ggplot(aes(x=item, y=par, ymin=CI_2.5, ymax=CI_97.5, col=group)) +\r\n  geom_point(position=pd) + geom_errorbar(width=0.1, position=pd) +\r\n  labs(y='Estimated difficulty') + \r\n  labs(x='Items')\r\n<\/code><\/pre>\n
\"plot<\/p>\n
\uc774\uac83\uc740 \ubaa8\uc9d1\ub2e8\uc758 \ub2a5\ub825 \ud3c9\uade0\uc744 \ubaa8\ub450 0\uc73c\ub85c \uc9c0\uc815\ud588\uae30 \ub54c\ubb38\uc5d0 \ubc1c\uc0dd\ud558\ub294 \ud604\uc0c1\uc774\ub2e4. (\ud558\uc9c0\ub9cc \uc6b0\ub9ac\ub294 \ubaa8\uc9d1\ub2e8\uc758 \ub2a5\ub825 \ud3c9\uade0\uc744 \ubbf8\ub9ac \uc54c \uc218 \uc5c6\uae30 \ub54c\ubb38\uc5d0 \ub2e4\ub978 \ubc29\ub3c4\uac00 \uc5c6\ub2e4!)<\/p>\n
\ub530\ub77c\uc11c \ub2a5\ub825\uc774 \ub0ae\uc740 \ud53c\ud5d8\uc790 \uc9d1\ub2e8\uc5d0 \uac80\uc0ac\ub97c \uc2e4\uc2dc\ud574\ub3c4 \ub2a5\ub825\uc774 \ub192\uc740 \ud53c\ud5d8\uc790 \uc9d1\ub2e8\uc5d0 \uac80\uc0ac\ub97c \uc2e4\uc2dc\ud574\ub3c4 \ubb38\ud56d\ub09c\uc774\ub3c4, \ubb38\ud56d\ubcc0\ubcc4\ub3c4, \ubb38\ud56d\ucd94\uce21\ub3c4\ub97c \ucd94\uc815\ud558\uc600\uc744 \ub54c \uac12\uc774 \uac19\ub2e4<\/strong>\ub294 \ubb38\uc7a5\uc740 \uc624\ud574\uc758 \uc18c\uc9c0\uac00 \ub2e4\ubd84\ud558\ub2e4. (\uc774\ub807\uac8c \uc9d1\ub2e8 \ud3c9\uade0\uc774 \ub2e4\ub978 \uacbd\uc6b0 \ubfd0 \uc544\ub2c8\ub77c, \ucc28\ubcc4\ubb38\ud56d\uae30\ub2a5(Differential Item Functioning; DIF)\uc774\ub77c\ub294 \ud604\uc0c1\uc744 \uc0dd\uac01\ud574\ubd10\ub3c4 \ub41c\ub2e4. \ucc28\ubcc4\ubb38\ud56d\uae30\ub2a5\uc774\ub780 \ubb38\ud56d\uc758 \ub09c\uc774\ub3c4\ub098 \ubcc0\ubcc4\ub3c4\uac00 \uc9d1\ub2e8\uc5d0 \ub530\ub77c \ub2ec\ub77c\uc9c0\ub294 \ud604\uc0c1\uc744 \uc758\ubbf8\ud55c\ub2e4.)<\/p>\n
\ubb38\ud56d \ub09c\uc774\ub3c4 \ubd88\ubcc0\uc131<\/h3>\n
IRT\uc758 \uc9c4\uc9dc \uc7a5\uc810\uc740 \uc0ac\ub78c\uc758 \ub2a5\ub825\uacfc \ubb38\ud56d\uc758 \ub09c\uc774\ub3c4\ub97c \ud558\ub098\uc758 \uc9c1\uc120 \uc704\uc5d0 \uc704\uce58\uc2dc\ud0a8\ub2e4\ub294 \uac83\uc774\ub2e4. <\/p>\n
\uc774\ub807\uac8c \uc0dd\uac01\ud574\ubcf4\uc790. IRT\ub97c \ud3ec\ud568\ud55c \uac80\uc0ac\ub97c \ubd84\uc11d\ud560 \ub54c \uc6b0\ub9ac\uac00 \uad00\uc2ec\uc744 \uac00\uc9c0\ub294 \uac83\uc740 \ub2e4\uc74c\uc758 \uc138 \uac00\uc9c0\ub85c \ubd84\ub958\ud574 \ubcfc \uc218 \uc788\ub2e4.<\/p>\n
    \n
  1. \uac80\uc0ac \uc790\uccb4\uc758 \ud2b9\uc131<\/li>\n
  2. \ubb38\ud56d\uc758 \ud2b9\uc131<\/li>\n
  3. \uc218\ud5d8\uc790\uc758 \ud2b9\uc131<\/li>\n<\/ol>\n
    3\ubc88 \uc218\ud5d8\uc790\uc758 \ud2b9\uc131\uc774\ub780, \uc218\ud5d8\uc790\uc758 \ub2a5\ub825\uc744 \uc758\ubbf8\ud558\ub294 \uac83\uc774\uace0, 2\ubc88 \ubb38\ud56d\uc758 \ud2b9\uc131\uc774\ub780 \ubb38\ud56d\uc758 \ub09c\uc774\ub3c4, \ubcc0\ubcc4\ub3c4 \ub4f1\uc744 \uc758\ubbf8\ud55c\ub2e4. 1\ubc88 \uac80\uc0ac \uc790\uccb4\uc758 \ud2b9\uc131\uc774\ub780 \ubb38\ud56d\ub4e4\uc774 \ubaa8\uc5ec\uc11c \uc6b0\ub9ac\uac00 \uce21\uc815\ud558\ub824\ub294 \ub300\uc0c1(\ub2a5\ub825, \uc131\ud5a5, \uc801\uc131 \ub4f1)\uc744 \uc5bc\ub9c8\ub098 \uc815\ud655\ud558\uac8c \uadf8\ub9ac\uace0 \uc2e0\ube59\uc131 \uc788\uac8c \uce21\uc815\ud558\ub290\ub0d0\ub294 \uac83\uc774\ub2e4. <\/p>\n
    \uc774\ub54c \uc218\ud5d8\uc790\uc758 \ud2b9\uc131\uc740 \ub208\uc5d0 \ubcf4\uc774\uc9c0 \uc54a\uace0, \uc9c1\uc811 \uce21\uc815\ud560 \uc218\ub3c4 \uc5c6\ub294 \uac83\uc774\ub2e4. \ub9cc\uc57d \uc9d1\ub2e8\ub9c8\ub2e4 \ubd84\ud3ec\uac00 \ub2e4\ub974\ub2e4\uace0 \ud574\ub3c4 \uc6b0\ub9ac\uac00 \uc774\ub97c \ud655\uc2e4\ud788 \ub208\uc73c\ub85c \ubcfc \uc218 \uc5c6\ub2e4. \ubc18\uba74 \ubb38\ud56d\uc774\ub780 \uac19\uc740<\/strong> \ubb38\ud56d\uc740 \uc5b4\ub5a4 \uc9d1\ub2e8\uc5d0\uac8c \uc81c\uc2dc\ub418\uc5c8\ub358 \uac04\uc5d0 \uac19\ub2e4<\/strong>\ub77c\uace0 \uc6b0\uc120 \uac00\uc815\ud55c\ub2e4. (\uc5ec\uae30\uc11c \uac00\uc815\ud55c\ub2e4\uace0 \ud558\ub294 \uac83\uc740 \ucc28\ubcc4\ubb38\ud56d\uae30\ub2a5\uc5d0\uc11c \ubcf4\ub4ef\uc774 \ub2e4\ub97c \uc218\ub3c4 \uc788\uae30 \ub54c\ubb38\uc774\ub2e4. \uc608\ub97c \ub4e4\uc5b4 “\ub450 \uac1c\uc758 \uc5d0\uba38\ub784\ub4dc\uc640 \ud55c \uac1c\uc758 \uc5d0\uba38\ub784\ub4dc\ub97c \ud569\uce58\uba74 \uba87 \uac1c\uc778\uac00?"\ub77c\ub294 \uc9c8\ubb38\uc740 \uc5d0\uba38\ub784\ub4dc\ub97c \ub108\ubb34\ub098 \uc798 \uc54c\uace0 \uc788\uace0, \ud56d\uc0c1 \uba87 \uac1c\uc529 \uac00\uc9c0\uace0 \ub2e4\ub2c8\ub294 \uc544\uc774\ub4e4\uacfc \uc5d0\uba38\ub784\ub4dc\ub780 \ub2e8\uc5b4 \uc790\uccb4\ub97c \ubaa8\ub974\ub294 \uc544\uc774\ub4e4\uc5d0\uac8c \uac19\ub2e4\uace0 \uc0dd\uac01\ud560 \uc218 \uc5c6\uae30 \ub54c\ubb38\uc774\ub2e4.)<\/p>\n
    \ub2e4\uc74c\uc740 \uc55e\uc758 \ud3c9\uade0\uc774 \ub2e4\ub978 \ub450 \uc9d1\ub2e8\uc5d0 \ub300\ud55c 2PL \ubd84\uc11d \uacb0\uacfc\ub85c \uc5bb\uc5b4\uc9c4 \ubb38\ud56d \ub09c\uc774\ub3c4\uacfc \uc218\ud5d8\uc790\uc758 \ub2a5\ub825\uce58 \ucd94\uc815\uac12\uc744 \ud558\ub098\uc758 \uadf8\ub9bc\uc5d0 \ub098\ud0c0\ub0b8 \uac83\uc774\ub2e4.<\/p>\n
    library(WrightMap)\r\n\r\ndiffA <- cfA[grepl('d', rownames(cfA)), "par"]\r\nnames(diffA) <- 1:10\r\n\r\ndiffB <- cfB[grepl('d', rownames(cfB)), "par"]\r\nnames(diffB) <- 1:10\r\n\r\nwrightMap(fscores(fitA), diffA)\r\n<\/code><\/pre>\n
    \"plot<\/p>\n
    ##          [,1]\r\n## 1  -1.4254750\r\n## 2  -0.7849791\r\n## 3   0.6550960\r\n## 4   0.1246907\r\n## 5  -1.6476004\r\n## 6  -2.7422941\r\n## 7   0.7555924\r\n## 8   1.5507982\r\n## 9  -1.3510807\r\n## 10 -0.3372793\r\n<\/pre>\n
    wrightMap(fscores(fitB), diffB)\r\n<\/code><\/pre>\n
    \"plot<\/p>\n
    ##          [,1]\r\n## 1  -0.1325570\r\n## 2   0.1415064\r\n## 3   1.4158933\r\n## 4   1.1563284\r\n## 5  -0.6001822\r\n## 6  -1.6807807\r\n## 7   1.6392685\r\n## 8   2.4272736\r\n## 9  -0.4676746\r\n## 10  0.6706505\r\n<\/pre>\n
    \uc5ec\uae30\uc11c \uc6b0\ub9ac\ub294 \ubb38\ud56d \ub09c\uc774\ub3c4\ub294 \ub2ec\ub77c\uc84c\uc9c0\ub9cc, \ubb38\ud56d \uc0ac\uc774\uc758 \uac70\ub9ac\ub294 \uc77c\uc815\ud558\uac8c \uc720\uc9c0\ub428\uc744 \uc54c \uc218 \uc788\ub2e4. \uadf8\ub9ac\uace0 \ubb38\ud56d\uc744 \uae30\uc900\uc73c\ub85c \uc0ac\ub78c\uc758 \ub2a5\ub825 \ud3c9\uade0\uc744 \ubcf4\uba74 \uadf8 \ucc28\uc774\ub294 \uc2e4\uc81c \ucc28\uc774\uc640 \ube44\uc2b7\ud55c 1\uc774\ub2e4.<\/p>\n
    \ubb38\ud56d \ubcc0\ubcc4\ub3c4 \ubd88\ubcc0\uc131<\/h3>\n
    \ubcc0\ubcc4\ub3c4\uc758 \uacbd\uc6b0\ub3c4 \ub9c8\ucc2c\uac00\uc9c0\uc774\ub2e4. \ub9cc\uc57d \ud45c\ubcf8 \uc9d1\ub2e8\uc758 \ub2a5\ub825 \ubd84\uc0b0\uc774 \ub2e4\ub974\ub2e4\uba74 \ubb38\ud56d\uc758 \ubcc0\ubcc4\ub3c4\ub294 \ub2e4\ub974\uac8c \ucd94\uc815\ub420 \uac83\uc774\ub2e4. \ud558\uc9c0\ub9cc \ubb38\ud56d \uac04\uc758 \ub09c\uc774\ub3c4 \ucc28\uc774\ub97c \uace0\ub824\ud574\ubcfc \ub54c, \ubb38\ud56d\uc758 \ubcc0\ubcc4\ub3c4\uc758 \uc758\ubbf8\ub294 \ub3d9\uc77c\ud558\uac8c \uc720\uc9c0\ub41c\ub2e4. \uc608\ub97c \ub4e4\uc5b4 \ubb38\ud56d \uac04\uc758 \ub09c\uc774\ub3c4 \ucc28\uc774\uac00 \uc99d\uac00\ub418\uba74 \ubcc0\ubcc4\ub3c4\ub3c4 \uac10\uc18c\ud558\uace0, \ubb38\ud56d \uac04\uc758 \ub09c\uc774\ub3c4 \ucc28\uc774\uac00 \uc904\uc5b4\ub4e4\uba74 \ubcc0\ubcc4\ub3c4\ub294 \uc99d\uac00\ud558\uac8c \ub41c\ub2e4. <\/p>\n
    d = rnorm(10)\r\nthA = matrix(rnorm(1000, mean=0, sd=0.7), 1000, 1)\r\nthB = matrix(rnorm(1000, mean=0, sd=1.4), 1000, 1)\r\nYA <- simdata(a=a, d=d, itemtype='2PL', Theta=thA)\r\nYB <- simdata(a=a, d=d, itemtype='2PL', Theta=thB)\r\n\r\nfitA <- mirt(YA, itemtype='2PL', model=1, SE=TRUE)\r\nfitB <- mirt(YB, itemtype='2PL', model=1, SE=TRUE)\r\n\r\ncfA <- coef(fitA, as.data.frame=TRUE)\r\ncfB <- coef(fitB, as.data.frame=TRUE)\r\n\r\ndat <- rbind(\r\n  cfA[grepl('[.]a', rownames(cfA)), ,drop=FALSE] %>% \r\n    as_tibble %>% \r\n    rownames_to_column(var='item') %>% \r\n    mutate(group='A'),\r\n  cfB[grepl('[.]a', rownames(cfB)), ,drop=FALSE] %>% \r\n    as_tibble %>% \r\n    rownames_to_column(var='item') %>% \r\n    mutate(group='B')\r\n) %>% \r\n  mutate(item = factor(item, levels=1:10))\r\n<\/code><\/pre>\n
    ## \r\nIteration: 1, Log-Lik: -5909.715, Max-Change: 0.17443\r\nIteration: 2, Log-Lik: -5899.020, Max-Change: 0.08096\r\nIteration: 3, Log-Lik: -5897.047, Max-Change: 0.04394\r\nIteration: 4, Log-Lik: -5896.413, Max-Change: 0.02336\r\nIteration: 5, Log-Lik: -5896.251, Max-Change: 0.01254\r\nIteration: 6, Log-Lik: -5896.205, Max-Change: 0.00747\r\nIteration: 7, Log-Lik: -5896.187, Max-Change: 0.00319\r\nIteration: 8, Log-Lik: -5896.183, Max-Change: 0.00241\r\nIteration: 9, Log-Lik: -5896.182, Max-Change: 0.00132\r\nIteration: 10, Log-Lik: -5896.181, Max-Change: 0.00057\r\nIteration: 11, Log-Lik: -5896.181, Max-Change: 0.00028\r\nIteration: 12, Log-Lik: -5896.181, Max-Change: 0.00023\r\nIteration: 13, Log-Lik: -5896.181, Max-Change: 0.00012\r\nIteration: 14, Log-Lik: -5896.181, Max-Change: 0.00010\r\n## \r\n## \r\n## Calculating information matrix...\r\n## \r\nIteration: 1, Log-Lik: -5689.507, Max-Change: 0.30165\r\nIteration: 2, Log-Lik: -5617.278, Max-Change: 0.16612\r\nIteration: 3, Log-Lik: -5599.240, Max-Change: 0.08868\r\nIteration: 4, Log-Lik: -5594.195, Max-Change: 0.04930\r\nIteration: 5, Log-Lik: -5592.647, Max-Change: 0.02773\r\nIteration: 6, Log-Lik: -5592.161, Max-Change: 0.01620\r\nIteration: 7, Log-Lik: -5591.955, Max-Change: 0.00689\r\nIteration: 8, Log-Lik: -5591.924, Max-Change: 0.00416\r\nIteration: 9, Log-Lik: -5591.913, Max-Change: 0.00239\r\nIteration: 10, Log-Lik: -5591.908, Max-Change: 0.00121\r\nIteration: 11, Log-Lik: -5591.907, Max-Change: 0.00067\r\nIteration: 12, Log-Lik: -5591.907, Max-Change: 0.00039\r\nIteration: 13, Log-Lik: -5591.907, Max-Change: 0.00022\r\nIteration: 14, Log-Lik: -5591.907, Max-Change: 0.00014\r\nIteration: 15, Log-Lik: -5591.907, Max-Change: 0.00011\r\nIteration: 16, Log-Lik: -5591.907, Max-Change: 0.00006\r\n## \r\n## \r\n## Calculating information matrix...\r\n<\/pre>\n
    pd = position_dodge(0.1)\r\ndat %>% ggplot(aes(x=item, y=par, ymin=CI_2.5, ymax=CI_97.5, col=group)) +\r\n  geom_point(position=pd) + geom_errorbar(width=0.1, position=pd) +\r\n  labs(y='Estimated discrimination') + \r\n  labs(x='Items')\r\n<\/code><\/pre>\n
    \"plot<\/p>\n
    \ub9c8\ubb34\ub9ac<\/h3>\n
    IRT\ub97c \ud1b5\ud574 \ub208\uc5d0 \ubcf4\uc774\uc9c0 \uc54a\ub294 \uc7a0\uc7ac\ubcc0\uc218(\uc608. \uc0ac\ub78c\uc758 \ub2a5\ub825)\ub97c \uad6c\uccb4\uc801\uc778 \ubb38\ud56d\uc744 \uae30\uc900\uc73c\ub85c \ud45c\uc2dc\ud560 \uc218 \uc788\ub2e4. \uc870\uce74\uc758 \uc5f0\uc0b0 \ub2a5\ub825\uc740 +1(\ubaa8\uc9d1\ub2e8\uc5d0\uc11c 1\ud45c\uc900\ud3b8\ucc28 \uc704)\ub77c\uace0 \ub9d0\ud558\ub294 \uac83\uacfc 11+12\ub294 \ud480 \ud655\ub960\uc774 50%\uc774\uace0 101+102\ub97c \ud480 \ud655\ub960\uc740 30%\ub77c\uace0 \ub9d0\ud558\ub294 \uac83\uc758 \ucc28\uc774\ub97c \uc0dd\uac01\ud574\ubcf4\uc790.<\/p>\n","protected":false},"excerpt":{"rendered":"
    \ubb38\ud56d\ubc18\uc751\uc774\ub860: \ubb38\ud56d\ud2b9\uc131\uc758 \ubd88\ubcc0\uc131 \ub2e4\uc74c\uc740 “\uc608\ube44\uad50\uc0ac\ub97c \uc704\ud55c \uad50\uc721\ud3c9\uac00"\uc758 \uc77c\ubd80(p.168)\ub97c \ubc1c\ucdcc\ud55c \ub0b4\uc6a9\uc774\ub2e4.[1] "\ubb38\ud56d\ubc18\uc751\uc774\ub860\uc740 \ub2a5\ub825\uc774 \ub0ae\uc740 \ud53c\ud5d8\uc790 \uc9d1\ub2e8\uc5d0 \uac80\uc0ac\ub97c \uc2e4\uc2dc\ud574\ub3c4 \ub2a5\ub825\uc774 \ub192\uc740 \ud53c\ud5d8\uc790 \uc9d1\ub2e8\uc5d0 \uac80\uc0ac\ub97c \uc2e4\uc2dc\ud574\ub3c4 \ubb38\ud56d\ub09c\uc774\ub3c4, \ubb38\ud56d\ubcc0\ubcc4\ub3c4, \ubb38\ud56d\ucd94\uce21\ub3c4\ub97c \ucd94\uc815\ud558\uc600\uc744 \ub54c \uac12\uc774 \uac19\ub2e4\ub294 \uac83\uc774\ub2e4.” [1]: \ube44\ub2e8 \uc774 \ucc45\ub9cc \uc544\ub2c8\uace0 \ub0b4\uac00 \ucc3e\uc544\ubcf8 \uac70\uc758 \ubaa8\ub4e0 \uad50\uc721 \ud3c9\uac00 \ucc45\uc5d0\ub294 \ub3d9\uc77c\ud55c \ub0b4\uc6a9\uc774 \ub3d9\uc77c\ud558\uac8c (\ub4a4\uc5d0\uc11c \uc0b4\ud3b4\ubcf4\uaca0\uc9c0\ub9cc) \ubd80\uc2e4\ud55c \uc124\uba85\uc73c\ub85c \uc801\ud600 \uc788\uc5c8\ub2e4. Christine DeMars\uac00 \uc124\uba85\ud55c […]<\/p>\n","protected":false},"author":1,"featured_media":2007,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[319],"tags":[395,393,396,394,397],"jetpack_featured_media_url":"http:\/\/ds.sumeun.org\/wp-content\/uploads\/2019\/10\/IRT_invariance.png","_links":{"self":[{"href":"http:\/\/ds.sumeun.org\/index.php?rest_route=\/wp\/v2\/posts\/2004"}],"collection":[{"href":"http:\/\/ds.sumeun.org\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/ds.sumeun.org\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/ds.sumeun.org\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/ds.sumeun.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=2004"}],"version-history":[{"count":2,"href":"http:\/\/ds.sumeun.org\/index.php?rest_route=\/wp\/v2\/posts\/2004\/revisions"}],"predecessor-version":[{"id":2006,"href":"http:\/\/ds.sumeun.org\/index.php?rest_route=\/wp\/v2\/posts\/2004\/revisions\/2006"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/ds.sumeun.org\/index.php?rest_route=\/wp\/v2\/media\/2007"}],"wp:attachment":[{"href":"http:\/\/ds.sumeun.org\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=2004"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/ds.sumeun.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=2004"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/ds.sumeun.org\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=2004"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}