第三节 多组资料的比较
H检验(Kruskal-Wallis法)是用于完全随机设计的多个样本比较的非参数法。其具体步骤见例21.3。
例21.3 某地监测大气中SO2的日均浓度,按不同功能区设置采样点,结果见表21-4“浓度”栏所示,问各功能区SO2日均浓度有无差别?
表21-4 某地1990年1月份SO2日均浓度(μg/m3)
对照区 |
工业区 |
商业区 |
居民区 |
浓度(1) |
秩次(2) |
浓度(3) |
秩次(4) |
浓度(5) |
秩次(6) |
浓度(7) |
秩次(8) |
10 |
1 |
467 |
9 |
231 |
6 |
338 |
7 |
30 |
2 |
665 |
15 |
501 |
11 |
352 |
8 |
30 |
3 |
709 |
18 |
630 |
13.5 |
485 |
10 |
40 |
4 |
802 |
19 |
669 |
16 |
511 |
12 |
51 |
5 |
851 |
20 |
677 |
17 |
630 |
13.5 |
Ri |
15 |
|
81 |
|
63.5 |
|
50.5 |
ni |
5 |
|
5 |
|
5 |
|
5 |
(一)建立假设
H0:四个功能区SO2日均浓度总体分布相同
H1:四个功能区SO2日均浓度总体分布不同或不全相同
α=0.05
(二)编秩
先将各组数据由小到大排列,再将各组数据由小到大统一编秩,不同组的相同数据取其平均秩次。如本例有2个630,分别在第(5)、(7)栏,其平均秩次为(13+14)/2=13.5。
(三)求各组秩和(Ri)
分别将各组秩次相加得Ri
(四)计算统计量H值
按式(21.4)计算。式中ni为各组观察值个数,N=Σni
公式(21.4)
本例
(五)确定P值,作出推论
若组数K=3,每组例数≤5,可查附表21-3“秩和检验用H界值表”得出P值;若超出附表21-3的范围,可按v=k-1查x2界值表得出P值。本例k=4,超出附表21-3范围,按v=4-1=3查x2界值表,x20.01(3)=11.34,P<0.01,按α=0.05检验水准拒绝H0,可认为四种功能区SO2日均浓度有差别。
附表21-1 符号秩和检验临界值表
对子数n |
T0.05 |
T0.02 |
T0.01 |
对子数n |
T0.05 |
T0.02 |
T0.01 |
6 |
0 |
— |
— |
16 |
29 |
23 |
19 |
7 |
2 |
0 |
— |
17 |
34 |
27 |
23 |
8 |
3 |
1 |
0 |
18 |
40 |
32 |
27 |
9 |
5 |
3 |
1 |
19 |
46 |
37 |
32 |
10 |
8 |
5 |
3 |
20 |
52 |
43 |
37 |
11 |
10 |
7 |
5 |
21 |
58 |
49 |
42 |
12 |
13 |
9 |
7 |
22 |
65 |
55 |
48 |
13 |
17 |
12 |
9 |
23 |
73 |
62 |
54 |
14 |
21 |
15 |
12 |
24 |
81 |
69 |
61 |
15 |
25 |
19 |
15 |
25 |
89 |
76 |
68 |
附表21-2 等级总和数临界值(双侧检验)
n2较大n |
P |
n1= 较 小 n |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
10 |
11 |
12 |
13 |
14 |
15 |
4 |
0.05 |
|
|
10 |
|
|
|
|
|
|
|
|
|
|
|
0.01 |
|
|
— |
|
|
|
|
|
|
|
|
|
|
|
5 |
0.05 |
|
6 |
11 |
17 |
|
|
|
|
|
|
|
|
|
|
0.01 |
|
— |
— |
15 |
|
|
|
|
|
|
|
|
|
|
6 |
0.05 |
|
7 |
12 |
18 |
26 |
|
|
|
|
|
|
|
|
|
0.01 |
|
— |
10 |
16 |
23 |
|
|
|
|
|
|
|
|
|
7 |
0.05 |
|
7 |
13 |
20 |
27 |
36 |
|
|
|
|
|
|
|
|
0.01 |
|
— |
10 |
17 |
24 |
32 |
|
|
|
|
|
|
|
|
8 |
0.05 |
3 |
8 |
14 |
21 |
29 |
38 |
49 |
|
|
|
|
|
|
|
0.01 |
— |
— |
11 |
17 |
25 |
34 |
43 |
|
|
|
|
|
|
|
9 |
0.05 |
3 |
8 |
15 |
22 |
31 |
40 |
51 |
63 |
|
|
|
|
|
|
0.01 |
— |
6 |
11 |
18 |
26 |
35 |
45 |
56 |
|
|
|
|
|
|
10 |
0.05 |
3 |
9 |
15 |
23 |
32 |
42 |
53 |
65 |
78 |
|
|
|
|
|
0.01 |
— |
6 |
12 |
19 |
27 |
37 |
47 |
58 |
71 |
|
|
|
|
|
11 |
0.05 |
4 |
9 |
16 |
24 |
34 |
44 |
55 |
68 |
81 |
96 |
|
|
|
|
0.01 |
— |
6 |
12 |
20 |
28 |
38 |
49 |
61 |
74 |
87 |
|
|
|
|
12 |
0.05 |
4 |
10 |
17 |
26 |
35 |
46 |
58 |
71 |
85 |
99 |
115 |
|
|
|
0.01 |
— |
7 |
13 |
21 |
30 |
40 |
51 |
63 |
76 |
90 |
106 |
|
|
|
13 |
0.05 |
4 |
10 |
18 |
27 |
37 |
48 |
60 |
73 |
88 |
103 |
119 |
137 |
|
|
0.01 |
— |
7 |
14 |
22 |
31 |
41 |
53 |
65 |
79 |
93 |
109 |
125 |
|
|
14 |
0.05 |
4 |
11 |
19 |
28 |
38 |
50 |
63 |
76 |
91 |
106 |
123 |
141 |
160 |
|
0.01 |
— |
7 |
14 |
22 |
32 |
43 |
54 |
67 |
81 |
96 |
112 |
129 |
147 |
|
15 |
0.05 |
4 |
11 |
20 |
29 |
40 |
52 |
65 |
79 |
94 |
110 |
127 |
145 |
164 |
185 |
0.01 |
— |
8 |
15 |
23 |
33 |
44 |
56 |
70 |
84 |
99 |
115 |
133 |
151 |
171 |
16 |
0.05 |
4 |
12 |
21 |
31 |
42 |
54 |
67 |
82 |
97 |
114 |
131 |
150 |
169 |
|
0.01 |
— |
8 |
15 |
24 |
34 |
46 |
58 |
72 |
86 |
102 |
119 |
137 |
155 |
|
17 |
0.05 |
5 |
12 |
21 |
32 |
43 |
56 |
70 |
84 |
100 |
117 |
135 |
154 |
|
|
0.01 |
— |
8 |
16 |
25 |
36 |
47 |
60 |
74 |
89 |
105 |
122 |
140 |
|
|
18 |
0.05 |
5 |
13 |
22 |
33 |
45 |
58 |
72 |
87 |
103 |
121 |
139 |
|
|
|
0.01 |
— |
8 |
16 |
26 |
37 |
49 |
62 |
76 |
92 |
108 |
125 |
|
|
|
19 |
0.05 |
5 |
13 |
23 |
34 |
46 |
60 |
74 |
90 |
107 |
124 |
|
|
|
|
0.01 |
3 |
9 |
17 |
27 |
38 |
50 |
64 |
78 |
94 |
111 |
|
|
|
|
20 |
0.05 |
5 |
14 |
24 |
35 |
48 |
62 |
77 |
93 |
110 |
|
|
|
|
|
0.01 |
3 |
9 |
18 |
28 |
39 |
52 |
66 |
81 |
97 |
|
|
|
|
|
21 |
0.05 |
6 |
14 |
25 |
37 |
50 |
64 |
79 |
95 |
|
|
|
|
|
|
0.01 |
3 |
9 |
18 |
29 |
40 |
53 |
68 |
83 |
|
|
|
|
|
|
22 |
0.05 |
6 |
15 |
26 |
38 |
51 |
66 |
82 |
|
|
|
|
|
|
|
0.01 |
3 |
10 |
19 |
29 |
42 |
55 |
70 |
|
|
|
|
|
|
|
23 |
0.05 |
6 |
15 |
27 |
39 |
53 |
68 |
|
|
|
|
|
|
|
|
0.01 |
3 |
10 |
19 |
30 |
43 |
57 |
|
|
|
|
|
|
|
|
24 |
0.05 |
6 |
16 |
28 |
40 |
55 |
|
|
|
|
|
|
|
|
|
0.01 |
3 |
10 |
20 |
31 |
44 |
|
|
|
|
|
|
|
|
|
25 |
0.05 |
6 |
16 |
28 |
42 |
|
|
|
|
|
|
|
|
|
|
0.01 |
3 |
11 |
20 |
32 |
|
|
|
|
|
|
|
|
|
|
26 |
0.05 |
7 |
17 |
29 |
|
|
|
|
|
|
|
|
|
|
|
0.01 |
3 |
11 |
21 |
|
|
|
|
|
|
|
|
|
|
|
27 |
0.05 |
7 |
17 |
|
|
|
|
|
|
|
|
|
|
|
|
0.01 |
4 |
11 |
|
|
|
|
|
|
|
|
|
|
|
|
28 |
0.05 |
7 |
|
|
|
|
|
|
|
|
|
|
|
|
|
0.01 |
4 |
|
|
|
|
|
|
|
|
|
|
|
|
|
附表21-3 秩和检验用H界值表
n |
n1 |
n2 |
n3 |
P |
0.05 |
0.01 |
7 |
3 |
2 |
2 |
4.71 |
|
3 |
3 |
1 |
5.14 |
|
8 |
3 |
3 |
2 |
5.36 |
|
4 |
2 |
2 |
5.33 |
|
4 |
3 |
1 |
5.21 |
|
5 |
2 |
1 |
5.00 |
|
9 |
3 |
3 |
3 |
5.60 |
7.20 |
4 |
3 |
2 |
5.44 |
6.44 |
4 |
4 |
1 |
4.97 |
6.67 |
5 |
2 |
2 |
5.16 |
6.53 |
5 |
3 |
1 |
4.96 |
|
10 |
4 |
3 |
3 |
5.73 |
6.75 |
4 |
4 |
2 |
5.45 |
7.04 |
5 |
3 |
2 |
5.25 |
6.82 |
5 |
4 |
1 |
4.99 |
6.95 |
11 |
4 |
4 |
3 |
5.60 |
7.14 |
5 |
3 |
3 |
5.65 |
7.08 |
5 |
4 |
2 |
5.27 |
7.12 |
5 |
5 |
1 |
5.13 |
7.31 |
12 |
4 |
4 |
4 |
5.69 |
7.65 |
5 |
4 |
3 |
5.63 |
7.44 |
5 |
5 |
2 |
5.34 |
7.27 |
13 |
5 |
4 |
4 |
5.26 |
7.76 |
5 |
5 |
3 |
5.71 |
7.54 |
14 |
5 |
5 |
4 |
5.64 |
7.79 |
15 |
5 |
5 |
5 |
5.78 |
7.98 |