SAS中统计分析求助

shiyiming

给定数据集合Clover如下：
title1 'Nitrogen Content of Red Clover Plants';
   data Clover;
      input Strain $ Nitrogen @@;
      datalines;
   3DOK1  19.4 3DOK1  32.6 3DOK1  27.0 3DOK1  32.1 3DOK1  33.0
   3DOK5  17.7 3DOK5  24.8 3DOK5  27.9 3DOK5  25.2 3DOK5  24.3
   3DOK4  17.0 3DOK4  19.4 3DOK4   9.1 3DOK4  11.9 3DOK4  15.8
   3DOK7  20.7 3DOK7  21.0 3DOK7  20.5 3DOK7  18.8 3DOK7  18.6
   3DOK13 14.3 3DOK13 14.4 3DOK13 11.8 3DOK13 11.6 3DOK13 14.2
   COMPOS 17.3 COMPOS 19.4 COMPOS 19.1 COMPOS 16.9 COMPOS 20.8
   ;
        run;
(1) 几种三叶草的氮含量均值是否相同？试用方差分析表的结果解释。
(2) 用Duncan方法比较几个均值，解释结果。
(3)试检验几种三叶草氮含量的方差是否相等。

哪位高手请赐教，几个问题分别适用哪些过程步？先谢过了

shiyiming

data Clover;
input Strain $ Nitrogen @@;
datalines;
3DOK1 19.4 3DOK1 32.6 3DOK1 27.0 3DOK1 32.1 3DOK1 33.0
3DOK5 17.7 3DOK5 24.8 3DOK5 27.9 3DOK5 25.2 3DOK5 24.3
3DOK4 17.0 3DOK4 19.4 3DOK4 9.1 3DOK4 11.9 3DOK4 15.8
3DOK7 20.7 3DOK7 21.0 3DOK7 20.5 3DOK7 18.8 3DOK7 18.6
3DOK13 14.3 3DOK13 14.4 3DOK13 11.8 3DOK13 11.6 3DOK13 14.2
COMPOS 17.3 COMPOS 19.4 COMPOS 19.1 COMPOS 16.9 COMPOS 20.8
;
run;

proc anova data=clover;
class strain;
model nitrogen=strain;
means strain/duncan;
means strain/hovtest;
run;