R中的gam函数错误

Question

I have a problem with my R code about a multiple linear regression. First, I try to use the gam function but this gives me an error. Here is the code:

install.packages("nlme")
library("mgcv")
library("ggplot2")
#Import dataset
setwd("/Users/Sarah/Documents/Master T&O/Master 1/Statistics IV/Assignment 2 ")
weight_data = read.csv("WeightLossGroup190.csv", sep = "", dec = ".", header = TRUE)

#Name of used data
weight <- weight_data$weight  
date <- weight_data$date 
dayNr <- weight_data$dayNumber 
time <- weight_data$time 
#Check linearity 
gam1 <- gam(as.numeric(weight_data$weight) ~ s(as.numeric(weight_data$dayNumber)) + s(as.numeric(weight_data$time)))
summary(gam1)
plot.gam(gam1, se = FALSE, rug = TRUE, all.terms = TRUE)

This gives me the following error:

Error in smooth.construct.tp.smooth.spec(object, dk$data, dk$knots) : 
  A term has fewer unique covariate combinations than specified maximum degrees of freedom

Does anyone have an idea of what I'm doing wrong?

Answer 1

您可能想尝试在 gam 中使用“k =”控制节数。