Table 9. Evaluation of 1990 Final County Estimates: Errors by Use of Major Variables in Ratio Correlation Method

Source:  U.S. Bureau of the Census
Internet Release date:  June 20, 1997

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                     |        |          |                              MEASURES OF DIFFERENCE
                     |        |          |--------------------------------------------------------------------------------------------- 
                     | Number |   Number |          Mean |          Mean |   Weighted | Root Mean | Index of |       50th |
                     |     of |       of |     Algebraic |      Absolute | Mean Abso- |    Square | Dissimi- | Percentile |       90th
Variables            | States | Counties | Percent Error | Percent Error | lute Error |     Error |   larity |   (Median) | Percentile
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                             VARIABLES INCLUDED WITHOUT REGARD TO WEIGHT
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Medicare                   24       1295             1.8             3.4          2.2         4.6        1.1          2.7          6.8
  without                  21       1296             2.2             3.6          2.1         4.9        1.1          2.7          7.4
School Enrollment          35       1937             2.0             3.3          2.0         4.5        1.0          2.6          6.8
  without                  10        654             2.0             4.0          2.8         5.5        1.4          3.1          8.5
Births                     33       1898             1.9             3.2          2.0         4.4        1.0          2.5          6.7
  without                  12        693             2.4             4.2          2.7         5.8        1.3          3.2          8.2
Deaths                     23       1331             2.2             3.6          2.4         4.6        1.2          2.9          7.0
  without                  22       1260             1.7             3.4          2.0         4.9        1.0          2.5          7.2
IRS Returns                31       1726             2.2             3.4          2.2         4.5        1.0          2.8          6.8
  without                  14        865             1.6             3.7          2.2         5.3        1.1          2.6          8.0
Auto Registration          18       1331             1.9             3.1          2.0         4.2        1.0          2.4          6.6
  without                  27       1260             2.1             3.9          2.4         5.4        1.2          3.0          7.7
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                             VARIABLES INCLUDED ONLY IF WEIGHT IS SUFFICIENTLY LARGE
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                     | Number |   Number |          Mean |          Mean |   Weighted | Root Mean | Index of |       50th |
                     |     of |       of |     Algebraic |      Absolute | Mean Abso- |    Square | Dissimi- | Percentile |       90th
Variables            | States | Counties | Percent Error | Percent Error | lute Error |     Error |   larity |   (Median) | Percentile
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Medicare                    4        230             2.1             3.8          3.0         5.1        1.5          2.7          9.2
  without                  41       2361             2.0             3.5          2.1         4.7        1.0          2.7          7.0
School Enrollment          33       1830             1.9             3.3          2.0         4.4        1.0          2.5          6.7
  without                  12        761             2.3             4.0          2.8         5.6        1.4          3.1          8.2
Births                     15        624             1.4             3.3          2.0         4.5        1.0          2.6          6.9
  without                  30       1967             2.2             3.6          2.3         4.9        1.1          2.7          7.2
Deaths                      8        285             2.5             4.2          2.5         5.4        1.3          3.3          9.1
  without                  37       2306             1.9             3.4          2.1         4.7        1.0          2.6          7.0
IRS Returns                30       1680             2.2             3.4          2.1         4.5        1.0          2.8          6.8
  without                  15        911             1.6             3.7          2.2         5.3        1.1          2.6          8.0
Auto Registration          12        893             2.1             3.2          2.1         4.3        1.0          2.5          7.0
  without                  33       1698             2.0             3.6          2.2         5.0        1.1          2.8          7.2
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