ejercicio de regresion

Buenas tardes

adjunto mi ejercicio de regresión de la etapa 3, bloque 6.4
https://drive.google.com/file/d/1bvRH0-E2AtWovP7PG8RibPYlS_0RH2Yy/view?usp=sharing
tengo atrasado el de clasificación, pero me da un error que no sé subsanar y que pego aquí para que esté a mano:
data(BreastCancer)
datos <- BreastCancer
#quitamos el id
datos <- datos[,-1]
datasetNOmiss <- datos[complete.cases(datos),]
# Split out validation dataset
# create a list of 80% of the rows in the original dataset we can use for training
set.seed(7)
validation_index <- createDataPartition(datos$Class, p=0.80, list=FALSE)
# select 20% of the data for validation
validation <- datos[-validation_index,]
# use the remaining 80% of data to training and testing the models
dataset <- datos[validation_index,]
# make predictions
set.seed(7)
x <- datasetNOmiss[,1:9]
# convert input values to numeric
for(i in 1:9) {
x[,i] <- as.numeric(as.character(x[,i]))
}
preprocessParams <- preProcess(x, method=c(«BoxCox»))

predictions <- predict(fit.cart, newdata=preProcess(validation, method=c(«BoxCox»)))
confusionMatrix(predictions, validation$Class)

predictions <- predict(fit.knn, newdata=preProcess(validation, method=c(«BoxCox»)))
caret::confusionMatrix(predictions, validation$Class)

y el error que da es este:

preprocessParams <- preProcess(x, method=c(«BoxCox»))
Warning in pre_process_options(method, column_types) :
The following pre-processing methods were eliminated: ‘BoxCox’
predictions <- predict(fit.knn, newdata=preProcess(validation, method=c(«BoxCox»)))
Warning in pre_process_options(method, column_types) :
The following pre-processing methods were eliminated: ‘BoxCox’
Error in as.data.frame.default(newdata, stringsAsFactors = FALSE) :
cannot coerce class ‘»preProcess»’ to a data.frame