The MI Procedure

Examples: MI Procedure

The Fish data described in the STEPDISC procedure are measurements of 159 fish of seven species caught in Finland’s lake Laengelmavesi. For each fish, the length, height, and width are measured. Three different length measurements are recorded: from the nose of the fish to the beginning of its tail (Length1), from the nose to the notch of its tail (Length2), and from the nose to the end of its tail (Length3). See Chapter 83, The STEPDISC Procedure, for more information.

The Fish1 data set is constructed from the Fish data set and contains only one species of the fish and the three length measurements. Some values have been set to missing, and the resulting data set has a monotone missing pattern in the variables Length1, Length2, and Length3. The Fish1 data set is used in Example 54.2 with the propensity score method and in Example 54.3 with the regression method.

The Fish2 data set is also constructed from the Fish data set and contains two species of fish. Some values have been set to missing, and the resulting data set has a monotone missing pattern in the variables Length3, Height, Width, and Species. The Fish2 data set is used in Example 54.4 with the logistic regression method and in Example 54.5 with the discriminant function method. Note that some values of the variable Species have also been altered in the data set.

The FitMiss data set created in the section Getting Started: MI Procedure is used in other examples. The following statements create the Fish1 data set:

/*----------- Fish of Species Bream ----------*/
 data Fish1;
    title 'Fish Measurement Data';
    input Length1 Length2 Length3 @@;
    datalines;
 23.2 25.4 30.0    24.0 26.3 31.2    23.9 26.5 31.1
 26.3 29.0 33.5    26.5 29.0   .     26.8 29.7 34.7
 26.8   .    .     27.6 30.0 35.0    27.6 30.0 35.1
 28.5 30.7 36.2    28.4 31.0 36.2    28.7   .    .
 29.1 31.5   .     29.5 32.0 37.3    29.4 32.0 37.2
 29.4 32.0 37.2    30.4 33.0 38.3    30.4 33.0 38.5
 30.9 33.5 38.6    31.0 33.5 38.7    31.3 34.0 39.5
 31.4 34.0 39.2    31.5 34.5   .     31.8 35.0 40.6
 31.9 35.0 40.5    31.8 35.0 40.9    32.0 35.0 40.6
 32.7 36.0 41.5    32.8 36.0 41.6    33.5 37.0 42.6
 35.0 38.5 44.1    35.0 38.5 44.0    36.2 39.5 45.3
 37.4 41.0 45.9    38.0 41.0 46.5
 ;

The Fish2 data set contains two of the seven species in the Fish data set. For each of the two species (Bream and Roach), the length from the nose of the fish to the end of its tail, the height, and the width of each fish are measured. The height and width are recorded as percentages of the length variable.

The following statements create the Fish2 data set:

/*-------- Fish of Species Bream and Roach --------*/
 data Fish2 (drop=HtPct WidthPct);
 title 'Fish Measurement Data';
 input Species $ Length3 HtPct WidthPct @@;
 Height= HtPct*Length3/100;
 Width= WidthPct*Length3/100;
 datalines;
 Gp1  30.0 38.4 13.4   Gp1  31.2 40.0 13.8   Gp1  31.1 39.8 15.1
   .  33.5 38.0   .      .  34.0 36.6 15.1   Gp1  34.7 39.2 14.2
 Gp1  34.5 41.1 15.3   Gp1  35.0 36.2 13.4   Gp1  35.1 39.9 13.8
   .  36.2 39.3 13.7   Gp1  36.2 39.4 14.1     .  36.2 39.7 13.3
 Gp1  36.4 37.8 12.0     .  37.3 37.3 13.6   Gp1  37.2 40.2 13.9
 Gp1  37.2 41.5 15.0   Gp1  38.3 38.8 13.8   Gp1  38.5 38.8 13.5
 Gp1  38.6 40.5 13.3   Gp1  38.7 37.4 14.8   Gp1  39.5 38.3 14.1
 Gp1  39.2 40.8 13.7     .  39.7 39.1   .    Gp1  40.6 38.1 15.1
 Gp1  40.5 40.1 13.8   Gp1  40.9 40.0 14.8   Gp1  40.6 40.3 15.0
 Gp1  41.5 39.8 14.1   Gp2  41.6 40.6 14.9   Gp1  42.6 44.5 15.5
 Gp1  44.1 40.9 14.3   Gp1  44.0 41.1 14.3   Gp1  45.3 41.4 14.9
 Gp1  45.9 40.6 14.7   Gp1  46.5 37.9 13.7
 Gp2  16.2 25.6 14.0   Gp2  20.3 26.1 13.9   Gp2  21.2 26.3 13.7
 Gp2  22.2 25.3 14.3   Gp2  22.2 28.0 16.1   Gp2  22.8 28.4 14.7
 Gp2  23.1 26.7 14.7     .  23.7 25.8 13.9   Gp2  24.7 23.5 15.2
 Gp2  24.3 27.3 14.6   Gp2  25.3 27.8 15.1   Gp2  25.0 26.2 13.3
 Gp2  25.0 25.6 15.2   Gp2  27.2 27.7 14.1   Gp2  26.7 25.9 13.6
   .  26.8 27.6 15.4   Gp2  27.9 25.4 14.0   Gp2  29.2 30.4 15.4
 Gp2  30.6 28.0 15.6   Gp2  35.0 27.1 15.3
 ;

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