vcov-method {mirt}R Documentation

Extract parameter variance covariance matrix

Description

Extract parameter variance covariance matrix

Usage

## S4 method for signature 'SingleGroupClass'
vcov(object)

Arguments

object

an object of class SingleGroupClass, MultipleGroupClass, or MixedClass

References

Chalmers, R., P. (2012). mirt: A Multidimensional Item Response Theory Package for the R Environment. Journal of Statistical Software, 48(6), 1-29. doi:10.18637/jss.v048.i06

Examples

## No test: 
x <- mirt(Science, 1, SE=TRUE)
vcov(x)
##                a1.1         d1.2          d2.3          d3.4          a1.5
## a1.1   0.0354557222  0.031747211  0.0218991330 -1.337062e-02 -0.0020114572
## d1.2   0.0317472109  0.240747985  0.0496914145 -7.728604e-03 -0.0039962941
## d2.3   0.0218991330  0.049691414  0.0495440979 -3.353138e-03 -0.0026118813
## d3.4  -0.0133706166 -0.007728604 -0.0033531385  2.516506e-02  0.0016239413
## a1.5  -0.0020114572 -0.003996294 -0.0026118813  1.623941e-03  0.0330717252
## d1.6  -0.0027776758  0.000321554  0.0013455096  4.475090e-03  0.0222002454
## d2.7  -0.0008339773  0.002234984  0.0026641307  3.634982e-03  0.0084726682
## d3.8   0.0025280813  0.006109937  0.0050768040  2.151939e-03 -0.0194002583
## a1.9  -0.0292529857 -0.032667514 -0.0224516013  1.338132e-02  0.0001401001
## d1.10 -0.0438210135 -0.037345358 -0.0240181907  2.417470e-02 -0.0060425885
## d2.11 -0.0206416044 -0.015080644 -0.0081996180  1.457986e-02 -0.0023410675
## d3.12  0.0177727573  0.023980089  0.0183114800 -1.142724e-03  0.0022121845
## a1.13  0.0096842437  0.008486325  0.0055838516 -3.358253e-03 -0.0026345430
## d1.14  0.0070930997  0.010415451  0.0077963642  4.886260e-06 -0.0038164066
## d2.15  0.0021935448  0.005091505  0.0044161993  2.013700e-03 -0.0013475415
## d3.16 -0.0040629009 -0.001253710  0.0001366316  4.584220e-03  0.0020482028
##                d1.6          d2.7         d3.8          a1.9         d1.10
## a1.1  -0.0027776758 -0.0008339773  0.002528081 -0.0292529857 -0.0438210135
## d1.2   0.0003215540  0.0022349842  0.006109937 -0.0326675142 -0.0373453580
## d2.3   0.0013455096  0.0026641307  0.005076804 -0.0224516013 -0.0240181907
## d3.4   0.0044750896  0.0036349818  0.002151939  0.0133813229  0.0241746980
## a1.5   0.0222002454  0.0084726682 -0.019400258  0.0001401001 -0.0060425885
## d1.6   0.0572478298  0.0178719080 -0.008242431 -0.0042731331  0.0008943475
## d2.7   0.0178719080  0.0204197987  0.001805256 -0.0022635445  0.0034073931
## d3.8  -0.0082424309  0.0018052557  0.041235925  0.0021523979  0.0112367277
## a1.9  -0.0042731331 -0.0022635445  0.002152398  0.2343596830  0.3068823433
## d1.10  0.0008943475  0.0034073931  0.011236728  0.3068823433  0.5333187950
## d2.11  0.0043839471  0.0058509494  0.008542531  0.1425287134  0.2140840707
## d3.12  0.0095948178  0.0084870680  0.005845643 -0.1227407709 -0.1520698557
## a1.13 -0.0031158076 -0.0007826477  0.003057944 -0.0316626320 -0.0478697496
## d1.14  0.0007925371  0.0027067338  0.006134230 -0.0304997627 -0.0348586852
## d2.15  0.0024475628  0.0032306664  0.004352544 -0.0097796669 -0.0072522805
## d3.16  0.0048748828  0.0037848620  0.002008196  0.0177300358  0.0307235701
##               d2.11        d3.12         a1.13         d1.14         d2.15
## a1.1  -0.0206416044  0.017772757  0.0096842437  7.093100e-03  0.0021935448
## d1.2  -0.0150806438  0.023980089  0.0084863254  1.041545e-02  0.0050915045
## d2.3  -0.0081996180  0.018311480  0.0055838516  7.796364e-03  0.0044161993
## d3.4   0.0145798573 -0.001142724 -0.0033582533  4.886260e-06  0.0020137003
## a1.5  -0.0023410675  0.002212184 -0.0026345430 -3.816407e-03 -0.0013475415
## d1.6   0.0043839471  0.009594818 -0.0031158076  7.925371e-04  0.0024475628
## d2.7   0.0058509494  0.008487068 -0.0007826477  2.706734e-03  0.0032306664
## d3.8   0.0085425306  0.005845643  0.0030579443  6.134230e-03  0.0043525441
## a1.9   0.1425287134 -0.122740771 -0.0316626320 -3.049976e-02 -0.0097796669
## d1.10  0.2140840707 -0.152069856 -0.0478697496 -3.485869e-02 -0.0072522805
## d2.11  0.1276826104 -0.062018021 -0.0219424374 -1.277452e-02  0.0003957921
## d3.12 -0.0620180213  0.104233499  0.0192987094  2.313630e-02  0.0117967217
## a1.13 -0.0219424374  0.019298709  0.0335900564  2.461211e-02  0.0088923418
## d1.14 -0.0127745164  0.023136304  0.0246121055  7.645466e-02  0.0179733534
## d2.15  0.0003957921  0.011796722  0.0088923418  1.797335e-02  0.0197363548
## d3.16  0.0175005019 -0.003280364 -0.0143630948 -5.930600e-03  0.0028978863
##               d3.16
## a1.1  -0.0040629009
## d1.2  -0.0012537103
## d2.3   0.0001366316
## d3.4   0.0045842200
## a1.5   0.0020482028
## d1.6   0.0048748828
## d2.7   0.0037848620
## d3.8   0.0020081962
## a1.9   0.0177300358
## d1.10  0.0307235701
## d2.11  0.0175005019
## d3.12 -0.0032803641
## a1.13 -0.0143630948
## d1.14 -0.0059305999
## d2.15  0.0028978863
## d3.16  0.0284229583
## End(No test)

[Package mirt version 1.40 Index]