chi2 not allowed with mrtab and weight

[Andres Benitez]

Hi, I try to do a chi2 test of significance. When I do not add weight, stata allows it, but when I try with "aw" or "iw" it returns error.

. mrtab temas1-temas3, poly response (1/83) by(cuatro) nolabel nofreq col chi2 mtest

            |                     cuatro                     
            |          1           2           3           4 |      Total   chi2/p*
------------+------------------------------------------------+-----------
         10 |      15.56       21.17       45.31        3.33 |      23.91    25.386
            |                                                |                0.000
------------+------------------------------------------------+-----------
         11 |       0.00        3.65        7.81        0.00 |       3.62     6.036
            |                                                |                0.110
------------+------------------------------------------------+-----------
         12 |      20.00        9.49        0.00       13.33 |       9.42    13.098
            |                                                |                0.004
------------+------------------------------------------------+-----------
         20 |      37.78       58.39       48.44       16.67 |      48.19    19.609
            |                                                |                0.000
------------+------------------------------------------------+-----------
         21 |       0.00        0.00        4.69        0.00 |       1.09    10.047
            |                                                |                0.018
------------+------------------------------------------------+-----------
         22 |      11.11        0.00        0.00        3.33 |       2.17    21.558
            |                                                |                0.000
------------+------------------------------------------------+-----------
         23 |       0.00        2.19        6.25        0.00 |       2.54     5.589
            |                                                |                0.133
------------+------------------------------------------------+-----------
         24 |      20.00        5.84        7.81       13.33 |       9.42     8.694
            |                                                |                0.034
------------+------------------------------------------------+-----------
         25 |      26.67       13.14        1.56       43.33 |      15.94    31.338
            |                                                |                0.000
------------+------------------------------------------------+-----------
         26 |       2.22       10.95        6.25       10.00 |       8.33     3.900
            |                                                |                0.273
------------+------------------------------------------------+-----------
         30 |      22.22       17.52        9.38       30.00 |      17.75     6.779
            |                                                |                0.079
------------+------------------------------------------------+-----------
         40 |      17.78       67.88       65.63       30.00 |      55.07    44.886
            |                                                |                0.000
------------+------------------------------------------------+-----------
         41 |       2.22       16.06        4.69        0.00 |       9.42    14.607
            |                                                |                0.002
------------+------------------------------------------------+-----------
         50 |       0.00        0.73        1.56        0.00 |       0.72     1.172
            |                                                |                0.760
------------+------------------------------------------------+-----------
         51 |       0.00        6.57       32.81        0.00 |      10.87    43.569
            |                                                |                0.000
------------+------------------------------------------------+-----------
         60 |       6.67        8.03        9.38        6.67 |       7.97     0.347
            |                                                |                0.951
------------+------------------------------------------------+-----------
         61 |      11.11        1.46        9.38       23.33 |       7.25    19.807
            |                                                |                0.000
------------+------------------------------------------------+-----------
         62 |       2.22        0.73        0.00       23.33 |       3.26    43.410
            |                                                |                0.000
------------+------------------------------------------------+-----------
         63 |       0.00        0.00        0.00        6.67 |       0.72    16.520
            |                                                |                0.001
------------+------------------------------------------------+-----------
         64 |       2.22        2.19        0.00        0.00 |       1.45     2.097
            |                                                |                0.553
------------+------------------------------------------------+-----------
         70 |       0.00        1.46        7.81       23.33 |       5.07    27.891
            |                                                |                0.000
------------+------------------------------------------------+-----------
         80 |       4.44        0.00        6.25        0.00 |       2.17     9.802
            |                                                |                0.020
------------+------------------------------------------------+-----------
         81 |       2.22        4.38        0.00        3.33 |       2.90     3.071
            |                                                |                0.381
------------+------------------------------------------------+-----------
         82 |       6.67        5.84        1.56       10.00 |       5.43     3.260
            |                                                |                0.353
------------+------------------------------------------------+-----------
         83 |       0.00        1.46        4.69        0.00 |       1.81     4.455
            |                                                |                0.216
------------+------------------------------------------------+-----------
      Total |     211.11      259.12      281.25      260.00 |     256.52

"mrtab temas1-temas3 [aw=pesonac], poly response (1/83) by(cuatro) nofreq col chi2 mtest
option chi2 not allowed
r(198);"


Any solutions?

[William Lisowski]

According to the output of help mrtab

fweights and aweights are allowed with mrtab

so that explains why it doesn't work with iweights. And further down it tells us

chi2 requests the calculation of an overall Pearson chi-square statistic for the hypothesis that the distribution of response patterns is independent from the values of the by-variable (not allowed if aweights are specified).

So, with the chi2 option your only choice for weights is fweights.