我经营一家lm()在 R 中，这是总结的结果：
Multiple R-squared: 0.8918, Adjusted R-squared: 0.8917
F-statistic: 9416 on 9 and 10283 DF, p-value: < 2.2e-16
看起来这是一个很好的模型，但是如果我手动计算 R^2，我会得到：
model=lm(S~0+C+HA+L1+L2,data=train)
pred=predict(model,train)
rss <- sum((model$fitted.values - train$S) ^ 2)
tss <- sum((train$S - mean(train$S)) ^ 2)
1 - rss/tss
##[1] 0.247238
rSquared(train$S,(train$S-model$fitted.values))
## [,1]
## [1,] 0.247238
怎么了？
str(train[,c('S','Campionato','HA','L1','L2')])
Classes ‘tbl_df’, ‘tbl’ and 'data.frame': 10292 obs. of 5 variables:
$ S : num 19 18 9 12 12 8 21 24 9 8 ...
$ C : Factor w/ 6 levels "D","E","F","I",..: 4 4 4 4 4 4 4 4 4 4 ...
$ HA : Factor w/ 2 levels "A","H": 1 2 1 1 2 1 2 2 1 2 ...
$ L1 : num 0.99 1.41 1.46 1.43 1.12 1.08 1.4 1.45 0.85 1.44 ...
$ L2 : num 1.31 0.63 1.16 1.15 1.29 1.31 0.7 0.65 1.35 0.59 ...
