Fiz uma ANOVA descobrindo, por exemplo, uma interação entre gênero e série do que gostaria de saber em que séries meninos e meninas diferem, mas em muitos casos encontro valores-p (ajustados) de 0 e 1. Como / por que isso é possível? Não parece certo ...
as.factor(gender) 1 16 16.2 2.6377 0.104396
as.factor(grade) 7 50077 7153.9 1165.4184 < 2.2e-16 ***
as.factor(gender):as.factor(grade) 7 132 18.9 3.0795 0.003056 **
Residuals 7747 47555 6.1
---
Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1
Tukey multiple comparisons of means
95% family-wise confidence level
Fit: aov(formula = rating ~ as.factor(gender) * as.factor(grade), data = users_c[users_c$grade %in% 1:8, ])
$`as.factor(gender)`
diff lwr upr p adj
m-f -0.09135851 -0.2016276 0.01891058 0.1043964
$`as.factor(grade)`
diff lwr upr p adj
2-1 0.3823566 -0.5454435 1.310157 0.9169296
3-1 1.9796023 1.1649854 2.794219 0.0000000
4-1 3.9558543 3.1534606 4.758248 0.0000000
5-1 5.7843111 4.9829529 6.585669 0.0000000
6-1 7.0752044 6.2708610 7.879548 0.0000000
7-1 8.4868609 7.6776332 9.296089 0.0000000
8-1 9.3867231 8.5626511 10.210795 0.0000000
3-2 1.5972457 1.0395026 2.154989 0.0000000
4-2 3.5734976 3.0337642 4.113231 0.0000000
5-2 5.4019544 4.8637616 5.940147 0.0000000
6-2 6.6928478 6.1502200 7.235476 0.0000000
7-2 8.1045042 7.5546625 8.654346 0.0000000
8-2 9.0043665 8.4329024 9.575831 0.0000000
4-3 1.9762520 1.6694948 2.283009 0.0000000
5-3 3.8047088 3.5006705 4.108747 0.0000000
6-3 5.0956021 4.7837806 5.407424 0.0000000
7-3 6.5072586 6.1830461 6.831471 0.0000000
8-3 7.4071208 7.0474558 7.766786 0.0000000
5-4 1.8284568 1.5588754 2.098038 0.0000000
6-4 3.1193501 2.8410202 3.397680 0.0000000
7-4 4.5310066 4.2388618 4.823151 0.0000000
8-4 5.4308688 5.0998193 5.761918 0.0000000
6-5 1.2908933 1.0155630 1.566224 0.0000000
7-5 2.7025498 2.4132612 2.991838 0.0000000
8-5 3.6024120 3.2738803 3.930944 0.0000000
7-6 1.4116565 1.1141985 1.709114 0.0000000
8-6 2.3115187 1.9757711 2.647266 0.0000000
8-7 0.8998622 0.5525763 1.247148 0.0000000
$`as.factor(gender):as.factor(grade)`
diff lwr upr p adj
m:1-f:1 0.005917865 -1.77842639 1.7902621 1.0000000
f:2-f:1 0.318074165 -1.28953805 1.9256864 0.9999988
m:2-f:1 0.442924925 -1.11597060 2.0018205 0.9998619
f:3-f:1 1.769000750 0.35262166 3.1853798 0.0020136
m:3-f:1 2.174229216 0.76569156 3.5827669 0.0000147
f:4-f:1 3.738998543 2.34268666 5.1353104 0.0000000
m:4-f:1 4.163719997 2.77146170 5.5559783 0.0000000
f:5-f:1 5.769586591 4.37599400 7.1631792 0.0000000
m:5-f:1 5.816721075 4.42497532 7.2084668 0.0000000
f:6-f:1 7.169439003 5.77317769 8.5657003 0.0000000
m:6-f:1 7.000924045 5.60308216 8.3987659 0.0000000
f:7-f:1 8.330142924 6.92683436 9.7334515 0.0000000
m:7-f:1 8.674488370 7.26930678 10.0796700 0.0000000
f:8-f:1 9.535307293 8.11198164 10.9586329 0.0000000
m:8-f:1 9.251081088 7.82191240 10.6802498 0.0000000
f:2-m:1 0.312156300 -1.12690148 1.7512141 0.9999959
m:2-m:1 0.437007060 -0.94741539 1.8214295 0.9995001
f:3-m:1 1.763082885 0.54136279 2.9848030 0.0000892
m:3-m:1 2.168311350 0.95569081 3.3809319 0.0000001
f:4-m:1 3.733080678 2.53468294 4.9314784 0.0000000
m:4-m:1 4.157802132 2.96412989 5.3514744 0.0000000
f:5-m:1 5.763668726 4.56844048 6.9588970 0.0000000
m:5-m:1 5.810803210 4.61772882 7.0038776 0.0000000
f:6-m:1 7.163521138 5.96518233 8.3618599 0.0000000
m:6-m:1 6.995006180 5.79482611 8.1951862 0.0000000
f:7-m:1 8.324225059 7.11768240 9.5307677 0.0000000
m:7-m:1 8.668570505 7.45984987 9.8772911 0.0000000
f:8-m:1 9.529389428 8.29962271 10.7591561 0.0000000
m:8-m:1 9.245163223 8.00863850 10.4816879 0.0000000
m:2-f:2 0.124850760 -1.02282435 1.2725259 1.0000000
f:3-f:2 1.450926585 0.50586965 2.3959835 0.0000172
m:3-f:2 1.856155050 0.92289131 2.7894188 0.0000000
f:4-f:2 3.420924378 2.50621691 4.3356318 0.0000000
m:4-f:2 3.845645832 2.93713824 4.7541534 0.0000000
f:5-f:2 5.451512425 4.54096139 6.3620635 0.0000000
m:5-f:2 5.498646910 4.59092496 6.4063689 0.0000000
f:6-f:2 6.851364838 5.93673457 7.7659951 0.0000000
m:6-f:2 6.682849880 5.76580854 7.5998912 0.0000000
f:7-f:2 8.012068759 7.08671595 8.9374216 0.0000000
m:7-f:2 8.356414205 7.42822339 9.2846050 0.0000000
f:8-f:2 9.217233128 8.26179669 10.1726696 0.0000000
m:8-f:2 8.933006923 7.96888762 9.8971262 0.0000000
f:3-m:2 1.326075825 0.46649985 2.1856518 0.0000150
m:3-m:2 1.731304290 0.88471145 2.5778971 0.0000000
f:4-m:2 3.296073618 2.46998162 4.1221656 0.0000000
m:4-m:2 3.720795071 2.90157332 4.5400168 0.0000000
f:5-m:2 5.326661665 4.50517434 6.1481490 0.0000000
m:5-m:2 5.373796150 4.55544575 6.1921465 0.0000000
f:6-m:2 6.726514078 5.90050756 7.5525206 0.0000000
m:6-m:2 6.557999120 5.72932364 7.3866746 0.0000000
f:7-m:2 7.887217999 7.04935402 8.7250820 0.0000000
m:7-m:2 8.231563445 7.39056617 9.0725607 0.0000000
f:8-m:2 9.092382368 8.22140761 9.9633571 0.0000000
m:8-m:2 8.808156163 7.92766524 9.6886471 0.0000000
m:3-f:3 0.405228465 -0.13578346 0.9462404 0.4221367
f:4-f:3 1.969997793 1.46166478 2.4783308 0.0000000
m:4-f:3 2.394719246 1.89762897 2.8918095 0.0000000
f:5-f:3 4.000585840 3.49977062 4.5014011 0.0000000
m:5-f:3 4.047720325 3.55206739 4.5433733 0.0000000
f:6-f:3 5.400438253 4.89224417 5.9086323 0.0000000
m:6-f:3 5.231923295 4.71940255 5.7444440 0.0000000
f:7-f:3 6.561142174 6.03389412 7.0883902 0.0000000
m:7-f:3 6.905487620 6.37327442 7.4377008 0.0000000
f:8-f:3 7.766306543 7.18788499 8.3447281 0.0000000
m:8-f:3 7.482080337 6.88942637 8.0747343 0.0000000
f:4-m:3 1.564769328 1.07871270 2.0508260 0.0000000
m:4-m:3 1.989490781 1.51520464 2.4637769 0.0000000
f:5-m:3 3.595357375 3.11716862 4.0735461 0.0000000
m:5-m:3 3.642491860 3.16971239 4.1152713 0.0000000
f:6-m:3 4.995209787 4.50929846 5.4811211 0.0000000
m:6-m:3 4.826694830 4.33626022 5.3171294 0.0000000
f:7-m:3 6.155913709 5.65010831 6.6617191 0.0000000
m:7-m:3 6.500259155 5.98928021 7.0112381 0.0000000
f:8-m:3 7.361078078 6.80213257 7.9200236 0.0000000
m:8-m:3 7.076851872 6.50319055 7.6505132 0.0000000
m:4-f:4 0.424721453 -0.01192015 0.8613631 0.0668946
f:5-f:4 2.030588047 1.58971048 2.4714656 0.0000000
m:5-f:4 2.077722532 1.64271796 2.5127271 0.0000000
f:6-f:4 3.430440460 2.98119847 3.8796825 0.0000000
m:6-f:4 3.261925502 2.80779484 3.7160562 0.0000000
f:7-f:4 4.591144381 4.12045589 5.0618329 0.0000000
m:7-f:4 4.935489827 4.45924616 5.4117335 0.0000000
f:8-f:4 5.796308750 5.26892973 6.3236878 0.0000000
m:8-f:4 5.512082545 4.96913148 6.0550336 0.0000000
f:5-m:4 1.605866594 1.17800058 2.0337326 0.0000000
m:5-m:4 1.653001078 1.23118920 2.0748130 0.0000000
f:6-m:4 3.005719006 2.56923916 3.4421989 0.0000000
m:6-m:4 2.837204048 2.39569420 3.2787139 0.0000000
f:7-m:4 4.166422928 3.70789927 4.6249466 0.0000000
m:7-m:4 4.510768373 4.04654394 4.9749928 0.0000000
f:8-m:4 5.371587296 4.85503631 5.8881383 0.0000000
m:8-m:4 5.087361091 4.55492128 5.6198009 0.0000000
m:5-f:5 0.047134485 -0.37906079 0.4733298 1.0000000
f:6-f:5 1.399852412 0.95913504 1.8405698 0.0000000
m:6-f:5 1.231337454 0.78563790 1.6770370 0.0000000
f:7-f:5 2.560556334 2.09799705 3.0231156 0.0000000
m:7-f:5 2.904901779 2.43669086 3.3731127 0.0000000
f:8-f:5 3.765720703 3.24558412 4.2858573 0.0000000
m:8-f:5 3.481494497 2.94557538 4.0174136 0.0000000
f:6-m:5 1.352717928 0.91787572 1.7875601 0.0000000
m:6-m:5 1.184202970 0.74431204 1.6240939 0.0000000
f:7-m:5 2.513421849 2.05645683 2.9703869 0.0000000
m:7-m:5 2.857767295 2.39508230 3.3204523 0.0000000
f:8-m:5 3.718586218 3.20341827 4.2337542 0.0000000
m:8-m:5 3.434360013 2.90326187 3.9654582 0.0000000
m:6-f:6 -0.168514958 -0.62249009 0.2854602 0.9968060
f:7-f:6 1.160703921 0.69016548 1.6312424 0.0000000
m:7-f:6 1.505049367 1.02895400 1.9811447 0.0000000
f:8-f:6 2.365868290 1.83862318 2.8931134 0.0000000
m:8-f:6 2.081642085 1.53882109 2.6244631 0.0000000
f:7-m:6 1.329218879 0.85401081 1.8044269 0.0000000
m:7-m:6 1.673564325 1.19285330 2.1542753 0.0000000
f:8-m:6 2.534383248 2.00296656 3.0657999 0.0000000
m:8-m:6 2.250157043 1.70328327 2.7970308 0.0000000
m:7-f:7 0.344345446 -0.15203755 0.8407284 0.5648416
f:8-f:7 1.205164369 0.65953016 1.7507986 0.0000000
m:8-f:7 0.920938164 0.36023867 1.4816377 0.0000022
f:8-m:7 0.860818923 0.31038540 1.4112524 0.0000101
m:8-m:7 0.576592718 0.01122178 1.1419637 0.0401330
m:8-f:8 -0.284226205 -0.89329509 0.3248427 0.9688007
Respostas:
Tudo o que 0 e 1 significam é que eles estão muito próximos de 0 ou 1. Se você observar com atenção, verá que quando o p ajustado é 1, o efeito é quase 0 e quando o p ajustado é 0, o limite mais próximo do efeito está muito longe. Portanto, não há nada "errado" em si. Agora veja quantos dígitos significativos você tem. O 1 ou 0 significa apenas que está mais próximo desse valor do que pode ser representado por um número com tantos dígitos. Sinta-se à vontade para denunciar algo como <0,0001 ou> 0,9999.
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