第八章单因素方差分析
8.1黄花蒿中所含的青蒿素是当前抗疟首选药物，研究不同播期对黄花蒿种子产量的影响，试验采用完全随机化设计，得到以下结果(kg/小区)[47]：
重复
播种期
2月19日3月9
日
3月28日4月13日
1 0.26 0.14 0.1
2 0.03
2 0.49 0.24 0.11 0.02
3 0.36 0.21 0.15 0.04
对上述结果做方差分析。
答：所用程序及结果如下：
options linesize=76 nodate;
data mugwort;
do date=1 to 4;
do repetit=1 to 3;
input yield @@;
output;
end;
end;
cards;
0.26 0.49 0.36
0.14 0.24 0.21
0.12 0.11 0.15
0.03 0.02 0.04
;
run;
proc anova;
class date;
model yield=date;
means date/duncan;
run;
One-Way ANOVA
Analysis of Variance Procedure
Class Level Information
Class Levels Values
DATE 4 1 2 3 4
Number of observations in data set = 12
One-Way ANOVA
Analysis of Variance Procedure
Dependent Variable: YIELD
Sum of Mean
Source DF Squares Square F Value Pr > F Model 3 0.18515833 0.06171944 14.99 0.0012 Error 8 0.03293333 0.00411667
Corrected Total 11 0.21809167
R-Square C.V. Root MSE YIELD Mean
0.848993 35.48088 0.06416 0.18083
Source DF Anova SS Mean Squar e F Value Pr > F DATE 3 0.18515833 0.06171944 14.99 0.0012 One-Way ANOVA
Analysis of Variance Procedure
Duncan's Multiple Range Test for variable: YIELD
NOTE: This test controls the type I comparisonwise error rate, not the experimentwise error rate
Alpha= 0.05 df= 8 MSE= 0.004117
Number of Means 2 3 4
Critical Range .1208 .1259 .1287
Means with the same letter are not significantly different.
Duncan Grouping Mean N DATE
A 0.37000 3 1
B 0.19667 3 2
B
C B 0.12667 3 3
C
C 0.03000 3 4
对于方差分析表中各项内容的含义，在“SAS程序及释义”部分已经做了详细解释，这里不再重复。如果有不明白的地方，请复习“SAS程序及释义”的相关内容。
SAS分析结果指出，不同播种期其产量差异极显著。多重比较表明，2和3间差异不显著，3和4间差异不显著，1和其他各组间差异都显著。以上结果可以归纳成下表。
变差来源平方和自由度均方 F P
播期间0.185 158 33 3 0.061 719 44 14.99 0.001 2
重复间0.032 933 33 8 0.004 116 67
总和0.218 091 67 11
多重比较：
1 2 3 4
8.2下表是6种溶液及对照组的雌激素活度鉴定，指标是小鼠子宫重。对表中的数据做方差分析，若差异是显著的，则需做多重比较。
鼠号
溶液种类
Ⅰ(ck)ⅡⅢⅣⅤⅥⅦ
1 89.9 84.4 64.4 75.
2 88.4 56.4 65.6
2 93.8 116.0 79.8 62.4 90.2 83.2 79.4
3 88.
4 84.0 88.0 62.4 73.2 90.4 65.6
4 112.6 68.6 69.4 73.8 87.8 85.6 70.2 答：所用程序及结果如下：
options linesize=76 nodate;
data uterus;
infile 'e:\data\exr8-2e.dat';
do solution=1 to 7;
do repetit=1 to 4;
input weight @@;
output;
end;
end;
run;
proc anova;
class solution;
model weight=solution;
means solution/duncan;
run;
The SAS System
Analysis of Variance Procedure
Class Level Information
Class Levels Values
SOLUTION 7 1 2 3 4 5 6 7
Number of observations in data set = 28
The SAS System
Analysis of Variance Procedure
Dependent Variable: WEIGHT
Sum of Mean
Source DF Squares Square F Value Pr > F Model 6 2419.10500 403.18417 2.77 0.0385 Error 21 3061.30750 145.77655
Corrected Total 27 5480.41250
R-Square C.V. Root MSE WEIGHT Mean 0.441409 15.03118 12.0738 80.3250 Source DF Anova SS Mean Square F Value Pr > F SOLUTION 6 2419.10500 403.18417 2.77 0.0385 The SAS System
Analysis of Variance Procedure
Duncan's Multiple Range Test for variable: WEIGHT
NOTE: This test controls the type I comparisonwise error rate, not the experimentwise error rate
Alpha= 0.05 df= 21 MSE= 145.7765
Number of Means 2 3 4 5 6 7
Critical Range 17.75 18.64 19.20 19.60 19.89 20.12
Means with the same letter are not significantly different.
Duncan Grouping Mean N SOLUTION
A 96.175 4 1
A
