SAS / PC
十三、 範 例 十三 : 相關係數計算及迴歸分析 (PROC CORR、REG)
程式檔名稱 : SAMPLE13
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DATA TESTCORR; | ||||||||
INPUT | STARTW | DAYS | X1 | X2 | X3 | X4; |
輸入資料 |
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CARDS; | ||||||||
10 |
5 | 1 | 2 | . | 1 | STARTW |
試驗開始動物體重 |
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10 | 5 | 2 | 4 | 2 | . | DAY | 試驗開始動物週齡 | |
10 | 5 | 3 | 6 | 3 | 1 | X1 -X4 | 四項結束試驗之測量性狀 | |
10 | 5 | 4 | 8 | 3 | 10 | |||
10 | 10 | 2 | 3 | 4 | 2 | |||
10 | 10 | 3 | 5 | 4 | 6 | |||
10 | 10 | 4 | 7 | 5 | 8 | |||
10 | 10 | 5 | 9 | 5 | 9 | |||
20 | 15 | 3 | 4 | 6 | 4 | |||
20 | 15 | 4 | 6 | 6 | 11 | |||
20 | 15 | 5 | 8 | 7 | 15 | |||
20 | 15 | 6 | 10 | 7 | 12 | |||
20 | 20 | 4 | 5 | 8 | 3 | |||
20 | 20 | 5 | 7 | 8 | 4 | |||
20 | 20 | 6 | 9 | 9 | 2 | |||
20 | 20 | 7 | 11 | 9 | 1 | |||
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RUN;
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PROC CORR NOSIMPLE; |
VAR X1 X2 X3 X4; RUN; |
性狀 X1-X4之簡單相關計算, | ||||||
不輸出平均值等基本分析值 | ||||||||
(NOSIMPLE) (表 13-1) | ||||||||
PROC CORR NOSIMPLE NOMISS; VAR X1 X2 X3 X4; RUN; |
如有其中一欄位為缺值則整筆 | |||||||
資料刪去, 不加進入分析 ( | ||||||||
NOMISS) (表 13-2) | ||||||||
PROC CORR NOSIMPLE NOMISS; |
偏相關計算 (PARTIAL CORR.) | |||||||
VAR X2 X3 X4 ; |
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PARTIAL STARTW DAYS; | 清去試驗開始動物體重、週齡等 | |||||||
效應對各變數之影響 (PARTIAL) | ||||||||
(質量變數不能於此清去其效應) | ||||||||
WITH X1; | 以 X1 和 X2 X3 X4 等變數間作 | |||||||
RUN;
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上述效應清除的對應相關係數計
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算(表 13-3) | ||||||||
PROC REG | 迴歸分析 | |||||||
CORR; | 輸出自、應變數間之簡單相關矩 | |||||||
MODEL X1 =X3 X4 | 陣應變數為 X1,自變數為 X3 X4 | |||||||
/ SELECTION=STEPWISE; | 選 STEPWISE 方法作最適模式之 | |||||||
自變數選擇 | ||||||||
OUTPUT OUT=REGOUT |
將分析完之結果輸出於新檔案 |
REGOUT | ||||||
P=PRED |
將應變數預測值 (P) 之新欄位名稱命為 PRED |
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U95=UP |
將應變數 95 % 信賴區間上界(U95) 存為新欄位 UP |
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L95=DOWN | 將應變數 95 % 信賴區間下界(L95) 存為新欄位 DOWN | |||||||
R=RES; | 將殘差值 (R) 存為新欄位 RES | |||||||
RUN;
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(表 13-4)
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表 13-1 | ||||||||
Pearson Correlation Coefficients / Prob > |R| under Ho: Rho=0 | ||||||||
/ Number of Observations |
X1 | X2 | X3 | X4 | |
X1 | 1.00000 | 0.94868 | 0.79248 | 0.28379 |
0.0 | 0.0001 | 0.0004 | 0.3054 | |
16 |
16 | 15 | 15 | |
X2 | 0.94868 | 1.00000 | 0.52566 | 0.37168 |
0.0001 | 0.0 | 0.0442 | 0.1725 | |
16 | 16 | 15 | 15 | |
X3 | 0.79248 | 0.52566 | 1.00000 | -0.13040 |
0.0004 | 0.0442 | 0.0 | 0.6568 | |
15 | 15 | 15 | 14 | |
X4 | 0.28379 | 0.37168 | -0.13040 | 1.00000 |
0.3054 | 0.1725 | 0.6568 | 0.0 | |
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15
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15
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14
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15
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表 13-2 |
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Pearson Correlation Coefficients / Prob > |R| under Ho: Rho=0 |
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/ N = 14 | X1 | X2 | X3 | X4 |
X1 | 1.00000 | 0.92831 | 0.74514 | 0.15269 |
0.0 | 0.0001 | 0.0022 | 0.6023 | |
X2 | 0.92831 | 1.00000 | 0.44721 | 0.26971 |
0.0001 | 0.0 | 0.1089 | 0.3511 | |
X3 | 0.74514 | 0.44721 | 1.00000 | -0.13040 |
0.0022 | 0.1089 | 0.0 | 0.6568 | |
X4 | 0.15269 | 0.26971 | -0.13040 | 1.00000 |
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0.6023
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0.3511
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0.6568
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0.0
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表 13-3 |
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Pearson Partial Correlation Coefficients |
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/ Prob > |R| under Ho: Partial Rho=0 / N = 14 |
X2 | X3 | X4 | ||
X1 | 1.00000 | 0.88616 | 0.33236 | |
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0.0
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0.0001
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0.2912
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表 13-4 | ||||
Correlation |
X3 | X4 | X1 | |
X3 | 1.0000 | -0.1304 | 0.7451 | |
X4 | -0.1304 | 1.0000 | 0.1527 | |
X1 | 0.7451 | 0.1527 | 1.0000 | |
Stepwise Procedure for Dependent Variable X1 |
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Step 1 Variable X3 Entered |
R-square = 0.55524079 |
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C(p) = 2.83225827 |
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. 略 |