Multiple comparisons for algae cover

Data from Kneitel and Lessin (2010)

Obs | treat | richness | total | algae | y
--- | --- | --- | --- | --- | ---
1 | Control | 8 | 78 | 1 | 0.10017
2 | Control | 5 | 84 | 7 | 0.26776
3 | Control | 10 | 115 | 45 | 0.73531
4 | Control | 7 | 200 | 100 | 1.57080
5 | Control | 6 | 72 | 20 | 0.46365
6 | Low | 8 | 73 | 15 | 0.39770
7 | Low | 7 | 124 | 70 | 0.99116
8 | Low | 8 | 116 | 50 | 0.78540
9 | Low | 8 | 92 | 5 | 0.22551
10 | Low | 7 | 138 | 60 | 0.88608
11 | Medium | 7 | 124 | 85 | 1.17310
12 | Medium | 8 | 116 | 80 | 1.10715
13 | Medium | 8 | 145 | 60 | 0.88608
14 | Medium | 6 | 154 | 100 | 1.57080
15 | Medium | 7 | 129 | 90 | 1.24905
16 | High | 6 | 134 | 95 | 1.34528
17 | High | 7 | 138 | 95 | 1.34528
18 | High | 8 | 103 | 70 | 0.99116
19 | High | 8 | 119 | 75 | 1.04720
20 | High | 6 | 132 | 80 | 1.10715
21 | VeryHigh | 6 | 148 | 95 | 1.34528
22 | VeryHigh | 5 | 134 | 95 | 1.34528
23 | VeryHigh | 5 | 119 | 100 | 1.57080
24 | VeryHigh | 5 | 117 | 90 | 1.24905
25 | VeryHigh | 5 | 129 | 80 | 1.10715

Multiple comparisons for algae cover

Data from Kneitel and Lessin (2010)

The GLM Procedure

Class Level Information
Class | Levels | Values
--- | --- | ---
treat | 5 | Control High Low Medium VeryHigh

Number of Observations Read | 25
Number of Observations Used | 25

Multiple comparisons for algae cover

Data from Kneitel and Lessin (2010)

The GLM Procedure

Dependent Variable: y

Source | DF | Sum of Squares | Mean Square | F Value | Pr > F
--- | --- | --- | --- | --- | ---
Model | 4 | 2.13816313 | 0.53454078 | 4.76 | 0.0073
Error | 20 | 2.24444069 | 0.11222203 |  |
Corrected Total | 24 | 4.38260382 |  |  |

R-Square | Coeff Var | Root MSE | y Mean
--- | --- | --- | ---
0.487875 | 33.68371 | 0.334996 | 0.994533

Source | DF | Type I SS | Mean Square | F Value | Pr > F
--- | --- | --- | --- | --- | ---
treat | 4 | 2.13816313 | 0.53454078 | 4.76 | 0.0073

Source | DF | Type III SS | Mean Square | F Value | Pr > F
--- | --- | --- | --- | --- | ---
treat | 4 | 2.13816313 | 0.53454078 | 4.76 | 0.0073

Multiple comparisons for algae cover

Data from Kneitel and Lessin (2010)

The GLM Procedure

Multiple comparisons for algae cover

Data from Kneitel and Lessin (2010)

The GLM Procedure

Tukey's Studentized Range (HSD) Test for y

Note:This test controls the Type I experimentwise error rate.

Alpha | 0.05
Error Degrees of Freedom | 20
Error Mean Square | 0.112222
Critical Value of Studentized Range | 4.23186
Minimum Significant Difference | 0.634

Comparisons significant at the 0.05 level are indicated by ***.
treat Comparison | Difference Between Means | Simultaneous 95% Confidence Limits |
--- | --- | --- | ---
VeryHigh - Medium | 0.1263 | -0.5077 | 0.7603 |
VeryHigh - High | 0.1563 | -0.4777 | 0.7903 |
VeryHigh - Low | 0.6663 | 0.0323 | 1.3003 | ***
VeryHigh - Control | 0.6960 | 0.0620 | 1.3300 | ***
Medium - VeryHigh | -0.1263 | -0.7603 | 0.5077 |
Medium - High | 0.0300 | -0.6040 | 0.6640 |
Medium - Low | 0.5401 | -0.0939 | 1.1741 |
Medium - Control | 0.5697 | -0.0643 | 1.2037 |
High - VeryHigh | -0.1563 | -0.7903 | 0.4777 |
High - Medium | -0.0300 | -0.6640 | 0.6040 |
High - Low | 0.5100 | -0.1239 | 1.1440 |
High - Control | 0.5397 | -0.0943 | 1.1737 |
Low - VeryHigh | -0.6663 | -1.3003 | -0.0323 | ***
Low - Medium | -0.5401 | -1.1741 | 0.0939 |
Low - High | -0.5100 | -1.1440 | 0.1239 |
Low - Control | 0.0296 | -0.6044 | 0.6636 |
Control - VeryHigh | -0.6960 | -1.3300 | -0.0620 | ***
Control - Medium | -0.5697 | -1.2037 | 0.0643 |
Control - High | -0.5397 | -1.1737 | 0.0943 |
Control - Low | -0.0296 | -0.6636 | 0.6044 |

Multiple comparisons for algae cover

Data from Kneitel and Lessin (2010)

The GLM Procedure

Tukey's Studentized Range (HSD) Test for y

Note:This test controls the Type I experimentwise error rate, but it generally has a higher Type II error rate than REGWQ.

Alpha | 0.05
Error Degrees of Freedom | 20
Error Mean Square | 0.112222
Critical Value of Studentized Range | 4.23186
Minimum Significant Difference | 0.634