[R] gamma distribution don't allow negative value in GLMs?
chao gai
chaogai at duineveld.demon.nl
Sun Oct 15 14:23:59 CEST 2006
I think the 0 values for snail are hurting you.
Kees
On Sunday 15 October 2006 13:10, zhijie zhang wrote:
> Dear friends,
> when i use glm() to fit my data, i use
> glm(formula = snail ~ vegtype + mhveg + humidity + elevation + soiltem,
> *family = Gamma(link = inverse),* data =a,))
> It shows: error in eval(expr, envir, enclos) : *gamma distribution don't
> allow negative value*.
>
> But i use
> result<-glm(formula = snail ~ vegtype + mhveg + humidity + elevation +
> soiltem, family = poisson, data =a) #this works
> In fact , there isn't any negative value in my dataset, who can tell me
> the reason?
> Thanks very much!
> I copy my data here so you can check it:
> vegtype mhveg humidity soiltem elevation snail
> 1 diluo 35.0 0.279851 21.1 low 162
> 2 diluo 25.0 0.316092 23.1 low 113
> 3 yuhao 35.0 0.297238 21.7 low 105
> 4 huanghuacai 1.5 0.310687 23.1 low 5
> 5 huanghuacai 2.0 0.267868 28.3 low 1
> 6 yuhao 25.0 0.290135 21.9 low 10
> 7 huanghuacai 1.0 0.285207 27.7 low 6
> 8 huanghuacai 2.0 0.252973 28.3 low 1
> 9 huanghuacai 1.5 0.270000 28.1 low 1
> 10 huanghuacai 2.5 0.300000 29.1 low 1
> 11 huanghuacai 2.0 0.296154 29.1 low 0
> 12 huanghuacai 2.0 0.302874 27.5 low 3
> 13 huanghuacai 1.5 0.301499 28.9 low 0
> 14 huanghuacai 3.0 0.291513 30.3 low 1
> 15 huanghuacai 1.0 0.273438 31.1 low 3
> 16 huanghuacai 1.5 0.290116 27.9 low 19
> 17 huanghuacai 2.5 0.198932 31.9 low 0
> 18 huanghuacai 2.0 0.390000 30.5 high 4
> 19 huanghuacai 2.5 0.282595 30.7 high 0
> 20 huanghuacai 1.0 0.266097 24.7 high 14
> 21 yuhao 30.0 0.240516 26.9 high 51
> 22 yuhao 35.0 0.227541 26.7 high 84
> 23 yuhao 20.0 0.252833 28.3 low 30
> 24 diluo 40.0 0.303030 27.9 low 91
> 25 hucao 80.0 0.303867 24.5 low 114
> 26 diluo 25.0 0.334948 26.7 low 115
> 27 hucao 60.0 0.306897 26.5 low 23
> 28 hucao 75.0 0.314465 25.7 low 43
> 29 yuhao 30.0 0.251783 26.1 low 77
> 30 diluo 10.0 0.277778 26.1 low 62
> 31 yuhao 25.0 0.291716 26.1 low 78
> 32 hucao 90.0 0.288800 24.5 low 35
> 33 diluo 25.0 0.337830 26.3 high 75
> 34 yuhao 13.0 0.296599 27.7 high 23
> 35 hucao 70.0 0.279498 26.3 high 116
> 36 diluo 3.0 0.281481 28.1 high 25
> 37 hucao 70.0 0.296000 23.7 high 83
> 38 diluo 10.0 0.272662 27.7 low 56
> 39 hucao 70.0 0.289796 25.3 high 112
> 40 diluo 5.0 0.339716 27.9 high 84
> 41 yuhao 35.0 0.231427 24.9 high 88
> 42 hucao 80.0 0.273810 24.1 high 134
> 43 yuhao 40.0 0.272789 25.1 high 53
> 44 yuhao 45.0 0.226036 25.1 high 88
> 45 yuhao 55.0 0.285495 23.9 high 76
> 46 hucao 80.0 0.252185 23.9 high 106
> 47 diluo 15.0 0.289933 24.5 high 194
> 48 hucao 95.0 0.261756 23.1 high 35
> 49 hucao 55.0 0.239819 24.7 high 21
> 50 hucao 75.0 0.254307 23.9 high 41
> 51 huanghuacai 1.0 0.286432 23.7 low 18
> 52 huanghuacai 2.0 0.301342 23.1 low 2
> 53 huanghuacai 2.0 0.369565 23.3 low 5
> 54 huanghuacai 1.5 0.245833 24.3 low 4
> 55 huanghuacai 1.0 0.315679 24.1 low 4
> 56 huanghuacai 2.5 0.296124 23.7 low 4
> 57 huanghuacai 2.0 0.312667 25.7 low 3
> 58 huanghuacai 3.0 0.300870 25.7 low 0
> 59 huanghuacai 2.0 0.303743 26.5 low 2
> 60 huanghuacai 1.0 0.269799 25.3 low 7
> 61 hucao 75.0 0.281250 22.5 low 14
> 62 yuhao 35.0 0.350350 23.3 low 63
> 63 hucao 65.0 0.304545 22.7 low 17
> 64 diluo 7.0 0.310056 24.9 low 45
> 65 hucao 80.0 0.288000 22.9 low 27
> 66 hucao 80.0 0.284211 22.7 low 46
> 67 diluo 25.0 0.281379 23.5 low 161
> 68 hucao 80.0 0.290533 23.3 low 117
> 69 yuhao 27.0 0.316568 24.1 low 106
> 70 yuhao 28.0 0.285156 25.1 low 82
> 71 yuhao 30.0 0.266667 24.5 low 55
> 72 hucao 85.0 0.290345 23.9 low 54
> 73 yuhao 35.0 0.315789 24.1 low 81
> 74 diluo 15.0 0.286598 28.3 low 102
> 75 yuhao 45.0 0.314211 24.1 low 85
> 76 yuhao 25.0 0.268794 25.1 low 63
> 77 hucao 80.0 0.275691 23.9 low 59
> 78 hucao 100.0 0.316614 24.1 low 46
> 79 yuhao 40.0 0.336683 25.5 low 70
> 80 diluo 20.0 0.270874 26.1 high 167
> 81 yuhao 50.0 0.271483 24.3 high 125
> 82 hucao 80.0 0.238095 25.1 high 200
> 83 yuhao 30.0 0.241202 26.7 low 122
> 85 diluo 35.0 0.244531 28.1 high 186
> 86 yuhao 55.0 0.274038 24.9 low 208
> 87 hucao 80.0 0.303488 25.7 low 87
> 88 hucao 85.0 0.278846 25.3 low 25
> 89 diluo 5.0 0.270330 28.3 high 18
> 90 yuhao 35.0 0.296296 24.7 high 21
> 91 diluo 1.0 0.274306 27.9 low 23
> 92 diluo 3.0 0.262673 29.5 low 0
> 93 diluo 8.0 0.268750 27.7 high 21
> 94 hucao 70.0 0.265734 26.1 high 2
> 95 hucao 85.0 0.275373 24.3 low 6
> 96 diluo 10.0 0.284091 27.1 low 2
> 97 hucao 85.0 0.268229 25.3 low 0
> 98 hucao 90.0 0.293056 23.9 low 0
> 99 yuhao 35.0 0.277483 24.7 low 3
> 100 hucao 95.0 0.286822 24.3 high 1
> 101 hucao 88.0 0.285946 23.9 high 5
> 102 yuhao 35.0 0.268313 24.5 low 1
> 103 yuhao 25.0 0.285714 24.3 high 0
> 104 yuhao 25.0 0.294675 24.5 high 2
> 105 yuhao 38.0 0.275385 23.5 high 6
> 106 hucao 92.0 0.302415 23.3 low 15
> 107 hucao 83.0 0.276190 23.9 low 5
> 108 yuhao 55.0 0.285068 24.1 low 20
> 109 hucao 80.0 0.276552 23.5 low 5
> 110 hucao 95.0 0.281818 23.9 low 0
> 111 hucao 105.0 0.270293 23.1 low 13
> 112 hucao 95.0 0.291209 20.1 low 23
> 113 hucao 90.0 0.273196 20.9 low 48
> 114 yuhao 27.0 0.261986 20.5 low 49
> 115 yuhao 40.0 0.265187 20.5 low 9
> 116 yuhao 27.0 0.307143 20.9 low 27
> 117 yuhao 33.0 0.293194 20.7 low 34
> 118 yuhao 25.0 0.211399 20.9 low 38
> 119 yuhao 20.0 0.277372 21.7 low 30
> 120 hucao 95.0 0.346224 20.5 low 88
> 121 hucao 90.0 0.330380 21.3 low 91
> 122 yuhao 23.0 0.337884 23.3 low 70
> 123 hucao 80.0 0.322488 22.3 low 103
> 124 hucao 80.0 0.300000 22.1 low 51
> 125 hucao 100.0 0.326241 21.7 low 82
> 126 hucao 95.0 0.298571 21.9 low 104
> 127 hucao 95.0 0.296029 21.7 low 39
> 128 hucao 85.0 0.260082 21.7 low 73
> 129 hucao 93.0 0.304167 21.9 low 103
> 130 hucao 90.0 0.289941 22.3 low 65
> 131 hucao 85.0 0.339189 22.7 low 112
> 132 yuhao 30.0 0.314103 23.3 low 32
> 133 yuhao 28.0 0.293464 23.5 low 29
> 134 yuhao 45.0 0.310256 23.3 low 92
> 135 yuhao 42.0 0.375573 23.1 low 49
> 136 hucao 90.0 0.313846 23.1 low 47
> 137 yuhao 25.0 0.303601 23.9 low 54
> 138 hucao 85.0 0.339394 23.3 low 64
> 139 hucao 90.0 0.285934 23.1 low 68
> 140 yuhao 27.0 0.327915 23.9 low 62
> 141 hucao 85.0 0.372679 23.9 low 94
> 142 hucao 85.0 0.350147 22.5 low 174
> 143 yuhao 35.0 0.278014 23.7 low 38
> 144 hucao 100.0 0.327273 22.9 low 105
> 145 hucao 68.0 0.309286 24.9 low 105
> 146 hucao 85.0 0.279503 24.3 high 60
> 147 hucao 95.0 0.310870 23.3 high 42
> 148 hucao 95.0 0.309353 24.3 high 64
> 149 hucao 92.0 0.280745 23.5 low 37
> 150 yuhao 25.0 0.300355 24.3 high 107
> 151 yuhao 40.0 0.307692 24.7 high 86
> 152 hucao 40.0 0.273292 25.3 high 72
> 153 hucao 53.0 0.305096 24.7 high 109
> 154 hucao 50.0 0.306288 24.7 high 76
> 155 hucao 95.0 0.312268 22.3 low 60
> 156 hucao 90.0 0.301170 22.7 low 62
> 157 yuhao 38.0 0.305109 22.9 low 68
> 158 hucao 25.0 0.300719 25.3 low 21
> 159 hucao 80.0 0.252149 23.1 low 50
> 160 hucao 90.0 0.290306 23.3 low 63
> 161 hucao 33.0 0.293772 25.1 low 63
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