J'ai effectué une analyse ANOVA, par exemple une interaction entre le sexe et le grade que je veux savoir dans quelles notes les garçons et les filles diffèrent, mais dans de nombreux cas, je trouve des valeurs de p (ajustées) de 0 et 1. Comment / pourquoi est-ce possible? Cela ne semble pas juste ...
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
Réponses:
Tout ce que signifient 0 et 1, c'est qu'ils sont très très proches de 0 ou 1. Si vous regardez attentivement, vous verrez que lorsque le p ajusté est 1, alors l'effet est presque 0 et lorsque le p ajusté est 0, la limite la plus proche de l'effet est très loin. Par conséquent, il n'y a rien de "mauvais" en soi. Maintenant, regardez combien de chiffres significatifs vous avez. Le 1 ou 0 signifie simplement qu'il est plus proche de cette valeur que ce qui peut être représenté par un nombre avec autant de chiffres. N'hésitez pas à signaler quelque chose comme <0,0001 ou> 0,9999.
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