我有一条奇怪的ROC曲线,它不是从0开始的,我想知道这意味着什么?这条ROC曲线是由一个奈夫贝叶斯分类器生成的
数据集可以从这里下载。https:/drive.google.comfiled14HG2sQDeAo8iPnYcZjEXvAi7iuimKwyDview?usp=sharing。
library(tidyverse)
library(caret)
mammographic_masses<- read_csv("MyData.csv")
set.seed(123)
training.samples <- mammographic_masses$severity %>%
createDataPartition(p = 0.8, list = FALSE)
trainData <- mammographic_masses[training.samples, ]
testData <- mammographic_masses[-training.samples, ]
library(e1071)
nb_model = naiveBayes(as.factor(severity) ~., data=trainData)
nb_predicted <- predict(nb_model, testData)
nb_predicted <- as.numeric(levels(nb_predicted))[nb_predicted]
plotROC(testData$severity, nb_predicted)